Composite Material, Light-Emitting Element, Light-Emitting Device and Manufacturing Method Thereof

ABSTRACT

It is an object of the present invention to provide a composite material that can be used for manufacturing a heat-resistant light-emitting element, provide a composite material that can be used for manufacturing a heat-resistant light-emitting element that can be driven with stability for a long period of time, and further, provide a composite material that can be used for manufacturing a light-emitting element that easily prevents short circuit between electrodes and uses less power. The present invention provides a composite material that has a first metal oxide skeleton including a first metal atom and an organic compound that is bound to the first metal atom by forming a chelate, where the first metal oxide exhibits an electron accepting property to the organic compound.

TECHNICAL FIELD

The present invention relates to an element (light-emitting element)that has a luminescent material including an organic material betweenelectrodes and emits light by applying a current between the electrodes,and a light-emitting device manufactured by using the element. Inparticular, the present invention relates to a light-emitting elementand a light-emitting device that are superior in heat-resistance andless deteriorates in luminance with emitting time.

BACKGROUND ART

In recent years, a light-emitting device and a display that use alight-emitting element formed by using an organic material have beenactively developed. Since the light-emitting, which is manufactured byinterposing an organic compound layer between a pair of electrodes,itself emits light unlike a liquid crystal display device, no lightsource such as a backlight is necessary, and the element itself is quitethin. Therefore, the light-emitting element is advantageous when a thinand lightweight display is manufactured.

The emission mechanism of the light-emitting element is said to be asfollows: an electron injected from a cathode and a hole injected from ananode are recombined in the luminescence center in an organic compoundto form a molecular exciton; and energy is released to emit light whenthe molecular exciton returns to the ground state. As the excited state,a singlet excited state and a triplet excited state are known, and it isbelieved that light can be emitted through either excited state.

The organic compound layer sandwiched between the electrodes often has alaminated structure, and a function-separation laminated structure of “ahole transporting layer, a light-emitting layer, and an electrontransporting layer” is typical as this laminated structure. When a layerformed by using a highly hole transporting material and a layer formedby using a highly electron transporting material are disposedrespectively on the side of an electrode that functions as an anode andon the side of an electrode that functions as a cathode to interpose alight-emitting layer in which a hole and an electron are recombinedtherebetween, holes and electrons can be transported efficiently, andfurther the recombination probability of holes and electrons can also beincreased. This structure provides a quite high luminous efficiency, andis thus employed for most of light-emitting display devices currentlyunder development (for example, Non-Patent Document 1).

-   [Non-Patent Reference 1]

Chihaya Adachi et al., Japanese Journal of Applied Physics, Vol. 27, No.2, pp. L269-L271 (1988)

In addition, as other structures, there are a structure of stacking inthe order of a hole injecting layer, a hole transporting layer, alight-emitting layer, and an electron transporting layer from anelectrode that functions as an anode, and a structure of stacking in theorder of a hole injecting layer, a hole transporting layer, alight-emitting layer, an electron transporting layer, and an electroninjecting layer from an electrode that functions as an anode, and therespective layers are formed by using materials that specialize in therespective functions. It is to be noted a layer that has two or more ofthese functions, for example, a layer that has both functions of alight-emitting layer and an electron transporting layer, may be used.

The organic compound layer typically has a laminated structure asdescribes above. However, a layer formed to have a single layerstructure or a mixed layer may be used, and a light-emitting layer maybe doped with a fluorescent dye or the like.

However, this light-emitting element has problems with heat resistanceand durability. Since this light-emitting is formed by stacking organicthin films using organic compounds as described above, fragility of thethin films using the organic compounds is considered to be a cause ofthe problems.

On the other hand, there is also an example of manufacturing alight-emitting element by applying not an organic thin film but a layerin which organic compounds (a hole transporting compound, an electrontransporting compound, and a luminescent compound) are dispersed in askeleton formed by a siloxane bond (for example, Patent Document 1 andNon-Patent Document 2). Further, in Patent Document 1, it is alsoreported that the durability and heat resistance of the element areimproved.

-   [Patent Reference 1]

Japanese Patent Application Laid-Open No. 2000-306669

-   [Non-Patent Reference 2]

Tony Dantas de Morais et al., Advanced Materials, Vol. 11, No. 2, pp.107-112 (1999)

However, in the light-emitting elements disclosed in Patent Document 1and Non-Patent Document 2, current is hard to flow as compared withconventional light-emitting elements since the organic compounds aredispersed in the insulating skeleton formed by the siloxane bond.

In these light-emitting elements, since the luminance gets higher inproportion to an applied current, the fact that current is hard to flowmeans that the voltage for obtaining a predetermined luminance (drivingvoltage) also gets higher. Thus, the power consumption is increased.

In addition, in order to suppress short circuit of a light-emittingelement due to dust and the like, it is effective to make the filmthickness of the light-emitting element thicker. However, when the filmthickness is made thicker in the light-emitting element that has thestructure as shown in Patent Document 1 or Non-Patent Document 2, theincrease in driving voltage is further exposed.

DISCLOSURE OF INVENTION

In view of the problems described above, it is an object of the presentinvention to provide a composite material (also referred to as a hybridmaterial) that can be used for manufacturing a heat-resistantlight-emitting element, provide a composite material that can be usedfor manufacturing a durable light-emitting element that can be drivenwith stability for a long period of time, provide a composite materialthat can be used for manufacturing a light-emitting element that cansatisfy the heat-resistance and the durability together, and further,provide a composite material that can be used for a manufacturing alight-emitting element having less increase in power consumption withthe above objects.

In addition, it is an object of the present invention to provide acomposite material that can be used for manufacturing a light-emittingelement that easily prevents short circuit between electrodes and usesless power.

Further, it is an object or the present invention to provide aheat-resistant light-emitting element, provide a durable light-emittingelement that can be driven with stability for a long period of time,provide a light-emitting element that can satisfy the heat-resistenceand the durable together, and further, a light-emitting element havingless increase in power consumption with the above objects.

In addition, it is an object of the present invention to provide alight-emitting element that easily prevents short circuit betweenelectrodes and uses less power.

A composite material according to the present invention, which is ableto achieve the objects described above, includes a first metal oxideskeleton comprising a first metal atom and an organic compound that isbound to the first metal atom by forming a chelate, where the firstmetal oxide exhibits an electron accepting property to the organiccompound.

The above-described composite material has a feature that the organiccompound is an organic compound having an arylamine skeleton.

In addition, the above-described composite material has a feature thatthe first metal atom is a transition metal, specifically, one or more oftitanium, vanadium, molybdenum, tungsten, rhenium, ruthenium, andniobium.

Further, another composite material according to the present inventionincludes a first metal oxide skeleton comprising a first metal atom andan organic compound that is bound to the first metal atom by forming achelate, where the metal oxide exhibits an electron donating property tothe organic compound.

The above-described composite material has a feature that the organiccompound is an organic compound having one or more of a pyridineskeleton, a pyrazine skeleton, a triazine skeleton, an imidazoleskeleton, a triazole skeleton, an oxadiazole skeleton, a thiadiazoleskeleton, an oxazole skeleton, and a thiazole skeleton.

In addition, the above-described composite material has a feature thatthe first metal atom is an alkali metal or an alkali-earth metal,specifically, any one or more of lithium, calcium, and barium.

In addition, the above-described composite material may further includea second metal oxide, for example, may include aluminum oxide.

The composite materials according to the present invention, which aredescribed above, may further include a third metal oxide. As the thirdmetal oxide, silicon oxide is preferable.

Further, another composite material according to the present inventionincludes a first metal oxide skeleton comprising a first metal atom, anorganic compound that is bound to the first metal atom by forming achelate, and a second metal oxide comprising a second metal atom, wherethe second metal oxide exhibits an electron accepting property to theorganic compound.

The above-described composite material has a feature that the valence ofthe first metal atom is trivalent or more and hexavalent or less, andhas a feature that the first metal atom is a metal atom belonging toGroup 13 or 14, and specifically, is preferably any one of aluminum,gallium, and indium.

In addition, the above-described composite material has a feature thatthe organic compound is an organic compound having an arylamineskeleton.

In addition, the above-described composite material has a feature thatthe second metal atom is a transition metal, specifically, any one oftitanium, vanadium, molybdenum, tungsten, rhenium, ruthenium, andniobium.

Further, another composite material according to the present inventionincludes a first metal oxide skeleton comprising a first metal atom, anorganic compound that is bound to the first metal atom by forming achelate, and a second metal oxide comprising a second metal atom, wherethe second metal oxide exhibits an electron donating property to theorganic compound.

The above-described composite material has a feature that the valence ofthe first metal atom is trivalent or more and hexavalent or less, andhas a feature that the first metal atom is a metal atom belonging toGroup 13 or 14, and specifically, is preferably any one or more ofaluminum, gallium, and indium.

In addition, the above-described composite material has a feature thatthe organic compound is an organic compound having one or more of apyridine skeleton, a pyrazine skeleton, a triazine skeleton, animidazole skeleton, a triazole skeleton, an oxadiazole skeleton, athiadiazole skeleton, an oxazole skeleton, and a thiazole skeleton.

In addition, the above-described composite material has a feature thatthe second metal atom is an alkali metal or an alkali-earth metal,specifically, any one of lithium, calcium, and barium.

The composite materials according to the present invention, which aredescribed above, may further include a third metal oxide. As the thirdmetal oxide, silicon oxide is preferable.

Moreover, the composite materials according to the present invention canbe used for light-emitting elements. Accordingly, a light-emittingelement according to the present invention includes a light-emittinglayer including a luminescent material and a layer including thecomposite material described above between a pair of electrodes,

In the above-described light-emitting element, it is preferable that thelayer including the composite material be provided in contact with oneor both of the pair of electrodes.

Furthermore, the present invention also includes a light-emitting deviceincluding the light-emitting element described above.

A light-emitting element using the above-described composite materialaccording to the present invention serves as a heat-resistantlight-emitting element. Further, a light-emitting element using theabove-described composite material according to the present inventionserves as a light-emitting element that can be driven with stability fora long period of time. Further, a light-emitting element using theabove-described composite material according to the present inventionserves as a heat-resistant light-emitting element that can be drivenwith stability for a long period of time. Further, a light-emittingelement using the above-described composite material according to thepresent invention serves as a light-emitting element having lessincrease in power consumption in addition to the above effects.

The above-described light-emitting element according to the presentinvention can serve as a heat-resistant light-emitting element. Further,the above-described light-emitting element according to the presentinvention can serve as a light-emitting element that can be driven withstability for a long period of time. Further, the above-describedlight-emitting element can serve as a heat-resistant light-emittingelement that can be driven with stability for a long period of time.Further, the above-described light-emitting element can serve as alight-emitting element having less increase in power consumption inaddition to the above effects.

Further, a light-emitting element that easily prevents short circuitbetween electrodes and uses less power can be provided.

BRIEF DESCRIPTION OF DRAWINGS

In the accompanying drawings:

FIG. 1 is a schematic diagram of a composite material according to thepresent invention;

FIG. 2 is a schematic diagram showing electrons donated and accepted inthe composite material according to the present invention;

FIG. 3 is a schematic diagram of a composite material according to thepresent invention;

FIG. 4 is a schematic diagram showing electrons donated and accepted inthe composite material according to the present invention;

FIG. 5 is a schematic diagram of a composite material according to thepresent invention;

FIG. 6 is a schematic diagram showing electrons donated and accepted inthe composite material according to the present invention;

FIG. 7 is a schematic diagram of a composite material according to thepresent invention;

FIG. 8 is a schematic diagram showing electrons donated and accepted inthe composite material according to the present invention;

FIG. 9 is a schematic diagram of a composite material according to thepresent invention;

FIG. 10 is a schematic diagram of a composite material according to thepresent invention;

FIGS. 11A to 11E are diagrams illustrating a manufacturing process of athin film light-emitting element according to the present invention;

FIGS. 12A to 12C are diagrams illustrating the manufacturing process ofthe thin film light-emitting element according to the present invention;

FIGS. 13A and 13B are diagrams illustrating the structure of displaydevices;

FIGS. 14A and 14B are a top view and a cross-sectional view of alight-emitting device according to the present invention;

FIGS. 15A to 15E are diagrams illustrating electronic devices to whichthe present invention can be applied;

FIGS. 16A to 16C are diagrams illustrating the structure of displaydevices;

FIGS. 17A to 17F are diagrams illustrating examples of pixel circuitsfor a display device;

FIG. 18 is a diagram illustrating an example of a protection circuit fora display device;

FIGS. 19A and 19B are diagrams illustrating the structures oflight-emitting elements according to the present invention;

FIGS. 20A and 20B are diagrams illustrating the structures oflight-emitting elements according to the present invention; and.

FIGS. 21A and 21B are absorption spectra of an example and a comparativeexample.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment Modes of the present invention will be described below withreference to the accompanying drawings. However, the present inventionmay be embodied in a lot of different forms, and it is to be easilyunderstood that various changes and modifications will be apparent tothose skilled in the art unless such changes and modifications departfrom the scope of the present invention. Therefore, the presentinvention is not to be construed with limitation to what is described inthe embodiments.

It is to be noted that, of a pair of electrodes of a light-emittingelement in the present invention, an electrode to which a voltage isapplied to have a higher potential so that luminescence can be obtainedis referred to as an electrode that functions as an anode, and anelectrode to which a voltage is applied to have a lower potential sothat luminescence can be obtained is referred to as an electrode thatfunctions as a cathode.

Further, in the present invention, unless otherwise noted, a holeinjecting layer indicates a layer that is formed by using a substance inwhich the barrier against injecting holes from an electrode is lowerthan the barrier against injecting electrons and is located more on theside of an electrode that functions as an anode than a light-emittinglayer, and a hole transporting layer indicates a layer that is formed byusing a substance that has a higher hole transporting property ratherthan an electron transporting property and is located more on the sideof an electrode that functions as an anode than a light-emitting layer.In addition, a layer that has both of these functions may be used.Further, an electron injecting layer indicates a layer that is formed byusing a substance in which the barrier against injecting electrons froman electrode is lower than the barrier against injecting holes and islocated more on the side of an electrode that functions as a cathodethan a light-emitting layer, and an electron transporting layerindicates a layer that is formed by using a substance that has a higherelectron transporting property rather than a hole transporting propertyand is located more on the side of an electrode that functions as acathode than a light-emitting layer. In addition, a layer that has bothof these functions may be used.

Embodiment Mode 1

FIG. 1 shows a schematic diagram of a composite material according tothe present invention in the present embodiment. In the compositematerial according to the present invention in the present embodiment, ahole injecting and/or transporting organic compound as a chelate ligandis bound to part or all of metals in a first metal oxide skeletonforming a binding network, and further, the metal oxide is able toaccept electrons from the organic compound. In this composite material,a hole is generated by donating and accepting an electron as shown in aschematic diagram of FIG. 2, and the hole injecting property andconductivity of the composite material is thus improved. FIG. 2 shows amatrix of molybdenum oxide with 5-diphenylamino-8-quinolinol as aligand, and is a schematic diagram illustrating molybdenum oxideaccepting an electron from 5-diphenylamino-8-quinolinol.

This composite material has the metal oxide skeleton, and is thus aheat-resistant and durable material. In addition, since the holeinjecting and/or transporting organic compound as a chelate ligand isbound to the metal in the skeleton, the composite material is able topossess the hole injecting or transporting property of the organiccompound. Further, since the metal oxide forming the skeleton is able toaccept electrons from the organic compound, the hole injecting ortransporting property and conductivity of the composite material can beimproved.

This composite material can be used as a material for a hole injectinglayer or a hole transporting layer in a light-emitting element toprovide a heat-resistant light-emitting element, a light-emittingelement that can be driven with stability for a long period of time, aheat-resistant light-emitting element that can be driven with stabilityfor a long period of time, and a light-emitting element having lessincrease in power consumption in addition to the above effects.

It is to be noted that the increase in driving voltage is less even whena light emitting element using the composite material in the presentembodiment for a hole injecting layer or a hole transporting layer isformed so that the hole injecting or transporting layer has a thick filmthickness. Therefore, the film thickness of a layer between one of apair of electrodes of a light-emitting element, which is formed first,and a light-emitting layer of the light-emitting element can be madethick so that short circuit of the light-emitting element due to dustand the like can be reduced. When the film thickness is 100 nm or more,this defect can be reduced effectively. Further, the composite materialaccording to the present invention is improved in the conductivity andthe carrier injecting or transporting property, and thus, short circuitof the light-emitting element due to dust and the like can be reducedwithout increasing the driving voltage significantly, that is, withoutincreasing the power consumption significantly.

In addition, it is preferable to use an organic compound having anarylamine skeleton as the organic compound that is bound as a chelateligand in the first metal oxide skeleton and provides a hole injectingproperty and/or a hole transporting property. Examples of the compoundhaving the arylamine skeleton include compounds represented by thefollowing structure formulas (1) to (4). Of course, any other compoundsother than these compounds may be used as long as the compounds can bebound as a chelate ligand in the first metal oxide skeleton and providea hole injecting property and/or a hole transporting property. It is tobe noted that only one of these organic compounds may be used, or two ormore thereof may be used. In the case of using two or more of theorganic compounds, a composite material in which the two or more organiccompounds as chelate ligands are bound to part or all of metals in thefirst metal oxide skeleton can be obtained.

Structure Formulas (1) to (4)

In addition, it is preferable to use a transition metal as the metalspecies for the metal oxide that forms the metal oxide skeleton and isable to accept electrons from the organic compound that is bound as achelate ligand, and it is more preferable to use any one or more oftitanium, vanadium, molybdenum, tungsten, rhenium, ruthenium, andniobium. The metal oxide skeleton can be formed by using one or more oftransition metals.

In addition, another metal oxide may further be added to the compositematerial in the present embodiment. The metal oxide that exhibits anelectron accepting property to the organic compound included in thecomposite material in the present embodiment and the added metal oxidemay form a composite oxide or may individually form independent metaloxide skeletons. As the added metal oxide, an oxide of a metal belongingto Group 13 or 14 of the periodic table, which has a large valence, ispreferable. In particular, silicon oxide is preferable. FIG. 9 shows anexample in which the metal oxide (molybdenum oxide) that exhibits anelectron accepting property to the organic compound and the added metaloxide (silicon oxide) form a composite oxide. The binding network of themetal oxide is more easily formed by adding another metal oxide that hasa large valence. It is to be noted that the elements belonging to Group14 are considered as metals except for carbon in the specification.

Further, it is preferable that in the composite material in the presentembodiment, the amount of the organic compound described above, whichhas a hole injecting or transporting property, be 0.1 mol or more and 1mol or less with respect to 1 mol of the metal atoms of the metal oxidethat exhibits an electron accepting property to the organic compound.

Embodiment Mode 2

FIG. 3 shows a schematic diagram of a composite material according tothe present invention in the present embodiment. In the compositematerial according to the present invention in the present embodiment,an electron injecting or transporting organic compound as a chelateligand is bound to part or all of metals in a first metal oxide skeletonforming a binding network, and further, the metal oxide is able todonate electrons to the organic compound. In this composite material, anelectron is generated by donating and accepting the electron as shown ina schematic diagram of FIG. 4, and the electron injecting property andconductivity of the composite material is thus improved. FIG. 4 shows amatrix including calcium oxide with 8-quinolinol as a ligand, and is aschematic diagram illustrating calcium oxide donating an electron to8-quinolinol.

This composite material has the metal oxide skeleton, and is thus aheat-resistant and durable material. In addition, since the electroninjecting or transporting organic compound as a chelate ligand is boundto the metal in the skeleton, the composite material is able to possessthe electron injecting or transporting property of the organic compound.Further, since the organic compound is composed of a material that isable to be given electrons from the metal oxide skeleton, the electroninjecting or transporting property and conductivity of the compositematerial can be improved.

This composite material can be used as a material for an electroninjecting layer or an electron transporting layer in a light-emittingelement to provide a heat-resistant light-emitting element, alight-emitting element that can be driven with stability for a longperiod of time, a heat-resistant light-emitting element that can bedriven with stability for a long period of time, and a light-emittingelement having less increase in power consumption with the aboveeffects.

It is to be noted that the increase in driving voltage is less even whena light emitting element using the composite material in the presentembodiment for an electron injecting layer or an electron transportinglayer is formed so that the electron injecting or transporting layer hasa thick film thickness. Therefore, the film thickness of a layer betweenone of a pair of electrodes of a light-emitting element, which is formedfirst, and a light-emitting layer of the light-emitting element can bemade thick so that short circuit of the light-emitting element due todust and the like can be reduced. When the film thickness is 100 nm ormore, this defect can be reduced effectively. Further, the compositematerial according to the present invention is improved in theconductivity-and the carrier injecting or transporting property, andthus, short circuit of the light-emitting element due to dust and thelike can be reduced without increasing the driving voltagesignificantly, that is, without increasing the power consumptionsignificantly.

In addition, it is preferable to use an organic compound having at leastone of a pyridine skeleton, a pyrazine skeleton, a triazine skeleton, animidazole skeleton, a triazole skeleton, an oxadiazole skeleton, athiadiazole skeleton, an oxazole skeleton, and a thiazole skeleton asthe organic compound that is bound as a chelate ligand in the firstmetal oxide skeleton and provides an electron injecting property and/oran electron transporting property. Examples thereof include thefollowing structure formulas (5) to (13) as an organic compound having apyridine skeleton, the following structure formulas (14) to (16) as anorganic compound having a pyrizine skeleton, the following structureformulas (17) and (18) as an organic compound having an imidazoleskeleton, the following structure formula (19) as an organic compoundhaving an oxadiazole skeleton, the following structure formula (20) asan organic compound having a thiadiazole skeleton, the followingstructure formula (21) as an organic compound having an oxazoleskeleton, and the following structure formula (22) as an organiccompound as a thiazole skeleton. Of course, any other compounds otherthan these compounds may be used as long as the compounds can be boundas a chelate ligand in the first metal oxide skeleton and provide anelectron injecting property and/or an electron transporting property. Itis to be noted that only one of these organic compounds may be used, ortwo or more thereof may be used. In the case of using two or more of theorganic compounds, a composite material in which the organic compoundsas chelate ligands are bound to part or all of metals in the first metaloxide skeleton can be obtained.

Structure Formulas (5) to (13)

Structure Formulas (14) to (16)

Structure Formulas (17) and (18)

Structure Formula (19)

Structure Formula (20)

Structure Formula (21)

Structure Formula (22)

In addition, it is preferable to use one or more of alkali metals andalkali-earth metals for the metal oxide that forms the metal oxideskeleton and is able to donate electrons to the organic compound that isbound as a chelate ligand, and it is more preferable to use any one ormore of lithium, calcium, and barium. It is to be noted that two or morekinds of metals are used to form an oxide skeleton in the case of usinga metal that is not able to form an oxide skeleton by itself. Namely, asecond metal oxide may be further added to form an oxide skeleton. Forexample, as shown in FIG. 3, a composite oxide skeleton of aluminumoxide and calcium oxide may be provided as the metal oxide skeleton byincluding aluminum oxide as the second metal oxide.

In addition, a third metal oxide may further be added to the compositematerial in the present embodiment. The metal oxide that exhibits anelectron donating property to the organic compound included in thecomposite material in the present embodiment and the added third metaloxide may form a composite oxide or may individually form independentmetal oxide skeletons. As the added third metal oxide, an oxide of ametal belonging to Group 13 or 14 of the periodic table, which has alarge valence, is preferable. In particular, silicon oxide ispreferable. The binding network of the metal oxide is more easily formedby adding another metal oxide that has a large valence.

Further, it is preferable that in the composite material in the presentembodiment, the amount of the organic compound described above, whichhas an electron injecting or transporting property, be 0.1 mol or moreand 1 mol or less with respect to 1 mol of the metal atoms of the firstmetal oxide.

Embodiment Mode 3

FIG. 5 shows a schematic diagram of a composite material according tothe present invention in the present embodiment. In the compositematerial according to the present invention in the present embodiment, ahole injecting or transporting organic compound as a chelate ligand isbound to part or all of metals in a first metal oxide skeleton forming abinding network, and a second metal oxide that is able to acceptelectrons from the organic compound is further added. In this compositematerial, a hole is generated by donating and accepting an electron asshown in a schematic diagram of FIG. 6, and the hole injecting propertyand conductivity of the composite material is thus improved. FIG. 6 is aschematic diagram illustrating molybdenum oxide accepting an electronfrom 5-diphenylamino-8-quinolinol in the composite material including amatrix of aluminum oxide with 5-diphenylamino-8-quinolinol as a ligandand further including molybdenum oxide.

This composite material has the metal oxide skeleton, and is thus aheat-resistant and durable material. In addition, since the holeinjecting or transporting organic compound as a chelate ligand is boundto the metal in the skeleton, the composite material is able to possessthe hole injecting or transporting property of the organic compound.Further, since an electron is donated and accepted between the organiccompound and the second metal oxide that is able to accept electronsfrom the organic compound, the hole injecting or transporting propertyand conductivity of the composite material can be improved.

This composite material can be used as a material for a hole injectinglayer or a hole transporting layer in a light-emitting element toprovide a heat-resistant light-emitting element, a light-emittingelement that can be driven with stability for a long period of time, aheat-resistant light-emitting element that can be driven with stabilityfor a long period of time, and a light-emitting element having lessincrease in power consumption in addition to the above effects.

It is to be noted that the increase in driving voltage is less even whena light emitting element using the composite material in the presentembodiment for a hole injecting layer or a hole transporting layer isformed so that the hole injecting or transporting layer has a thick filmthickness. Therefore, the film thickness of a layer between one of apair of electrodes of a light-emitting element, which is formed first,and a light-emitting layer of the light-emitting element can be madethick so that short circuit of the light-emitting element due to dustand the like can be reduced. When the film thickness is 100 nm or more,this defect can be reduced effectively. Further, the composite materialaccording to the present invention is improved in the conductivity andthe carrier injecting or transporting property, and thus, short circuitof the light-emitting element due to dust and the like can be reducedwithout increasing the driving voltage significantly, that is, withoutincreasing the power consumption significantly.

As the organic compound that is bound as a chelate ligand in the firstmetal oxide skeleton and provides a hole injecting property and/or ahole transporting property, the same material as the organic compoundthat provides a hole injecting property and/or a hole transportingproperty to the composite material in the structure shown in FIG. 1 maybe preferably used. Specifically, it is preferable to use an organiccompound having an arylamine skeleton, and for example, the organiccompounds represented by the structure formulas (1) to (4) mentionedabove may be used.

In addition, it is preferable to use a transition metal oxide as thesecond metal oxide that is able to accept electrons from the organiccompound that is bound as a chelate ligand, and it is more preferablethat the second metal oxide be an oxide of any one or more of titanium,vanadium, molybdenum, tungsten, rhenium, ruthenium, and niobium for thesecond metal oxide.

In addition, the first metal atom forming the first metal oxide skeletonis not limited. However, in order to form the binding network, it ispreferable that the first metal atom be a metal atom that has a largevalence, and specifically, it is preferable that the valence of thefirst metal be trivalent or more and hexavalent or less. Further, ametal belonging to Group 13 or 14 is preferable, and particularly,aluminum, gallium, or indium is preferable. The oxide skeleton mayinclude one kind of metal, or two or more kinds of metals may beincluded.

In addition, a third metal oxide may further be added to the compositematerial in the present embodiment. It is to be noted that the first andsecond metal oxides described above ant the added third metal oxide mayform a composite oxide or may individually form independent metal oxideskeletons. As the added third metal oxide, an oxide of a metal belongingto Group 13 or 14 of the periodic table, which has a large valence, ispreferable. In particular, silicon oxide is preferable. FIG. 10 shows anexample in which the second metal oxide (molybdenum oxide) that exhibitsan electron accepting property to the organic compound is included, andthe first metal oxide (aluminum oxide) having the first metal atom(aluminum) to which the organic compound is bound as a chelate ligandand the third metal oxide (silicon oxide) form a composite oxide. Thebinding network of the metal oxide is more easily formed by adding thethird metal oxide, which has a large valence.

Further, it is preferable that in the composite material in the presentembodiment, the amount of the first organic compound described above,which has a hole injecting or transporting property, be 0.1 mol or moreand 1 mol or less with respect to 1 mol of the metal atoms of the firstmetal oxide, and be 0.1 mol or more and 10 mol or less with respect to 1mol of the metal atoms of the second metal oxide.

Embodiment Mode 4

FIG. 7 shows a schematic diagram of a composite material according tothe present invention in the present embodiment. In the compositematerial according to the present invention in the present embodiment,an electron injecting or transporting organic compound as a chelateligand is bound to part or all of metals in a first metal oxide skeletonforming a binding network, and a second metal oxide that is able todonate electrons to the organic compound is further added. In thiscomposite material, an electron is generated by donating and acceptingthe electron as shown in a schematic diagram of FIG. 8, and the electroninjecting property and conductivity of the composite material is thusimproved. FIG. 8 is a schematic diagram illustrating calcium oxidedonating an electron to 8-quinolinol in the composite material includinga matrix of aluminum oxide with 8-quinolinol as a ligand and furtherincluding molybdenumloxide.

This composite material has the metal oxide skeleton, and is thus aheat-resistant and durable material. In addition, since the electroninjecting or transporting organic compound as a chelate ligand is boundto the metal in the skeleton, the composite material is able to possessthe electron injecting or transporting property of the organic compound.Further, since an electron is donated and accepted between the organiccompound and the second metal oxide that is able to donate electrons tothe organic compound, the electron injecting or transporting propertyand conductivity of the composite material can be improved.

This composite material can be used as a material for an electroninjecting layer or an electron transporting layer in a light-emittingelement to provide a heat-resistant light-emitting element, alight-emitting element that can be driven with stability for a longperiod of time, a heat-resistant light-emitting element that can bedriven with stability for a long period of time, and a light-emittingelement having less increase in power consumption in addition to theabove effects.

It is to be noted that the increase in driving voltage is less even whena light emitting element using the composite material in the presentembodiment for an electron injecting layer or an electron transportinglayer is formed so that the electron injecting or transporting layer hasa thick film thickness. Therefore, the film thickness of a layer betweenone of a pair of electrodes of a light-emitting element, which is formedfirst, and a light-emitting layer of the light-emitting element can bemade thick so that short circuit of the light-emitting element due todust and the like can be reduced. When the film thickness is 100 nm ormore, this defect can be reduced effectively. Further, the compositematerial according to the present invention is improved in theconductivity and the carrier injecting or transporting property, andthus, short circuit of the light-emitting element due to dust and thelike can be reduced without increasing the driving voltagesignificantly, that is, without increasing the power consumptionsignificantly.

As the organic compound that is bound as a chelate ligand in the firstmetal oxide skeleton and provides an electron injecting property and/oran electron transporting property, the same material as the organiccompound that provides an electron injecting property and/or an electrontransporting property to the composite material in the structure shownin FIG. 3 may be preferably used. Specifically, it is preferable to usean organic compound having at least one of a pyridine skeleton, apyrazine skeleton, a triazine skeleton, an imidazole skeleton, atriazole skeleton, an oxadiazole skeleton, a thiadiazole skeleton, anoxazole skeleton, and a thiazole skeleton, and for example, the organiccompounds represented by the structure formulas (5) to (22) mentionedabove may be used.

In addition, it is preferable to use an oxide of one or more of alkalimetals and alkali-earth metals as the second metal oxide that is able todonate electrons to the organic compound that is bound as a chelateligand, and it is more preferable to use an oxide of any one or more oflithium, calcium, and barium.

In addition, the first metal forming the first metal oxide skeleton isnot limited. However, a metal belonging to Group 13 or 14 is preferable,and particularly, aluminum, gallium, or indium is preferable. The oxideskeleton may include one kind of metal, or two or more kinds of metalsmay be included.

In addition, a third metal oxide may further be added to the compositematerial in the present embodiment. It is to be noted that the first andsecond metal oxides described above ant the added third metal oxide mayform a composite oxide or may individually form independent metal oxideskeletons. As the added third metal oxide, an oxide of a metal belongingto Group 13 or 14 of the periodic table, which has a large valence, ispreferable. In particular, silicon oxide is preferable. The bindingnetwork of the metal oxide is more easily formed by adding the thirdmetal oxide, which has a large valence.

Further, it is preferable that, in the composite material in the presentembodiment, the amount of the first organic compound described above,which has an electron injecting or transporting property, be 0.1 mol ormore and 1 mol or less with respect to 1 mol of the metal atoms of thefirst metal oxide, and be 0.1 mol or more and 10 mol or less withrespect to 1 mol of the metal atoms of the second metal oxide.

It is to be noted that the metal oxide may include a hydroxyl group in aportion thereof in each of the composite materials according to thepresent invention as described above in Embodiment Modes 1 to 4.

Embodiment Mode 5

In the present embodiment, a method of manufacturing the compositematerial according to the present invention, which is described inEmbodiment Mode 1 or 2, by a sol-gel method using a metal alkoxide willbe described.

The following formulas (23) and (24) show a scheme of the method. In thepresent embodiment, a case of manufacturing the composite material(Embodiment Mode 1) using a molybdenum oxide skeleton as the first metaloxide skeleton and 5-diphenylamino-8-quinolinol as the organic compoundthat has a hole injecting or transporting property and is able to bebound to a molybdenum atom as a chelate ligand, from which themolybdenum oxide is able to accept electrons, will be described as anexample. The same basic principle is applied also to a case of usinganother metal oxide skeleton, a case of using a metal oxide skeletonhaving two or more kinds of metals, and a case of using another organiccompound.

Formula (23)

Formula (24)

The formula (23) shows a pathway of dissolving and reacting a metalalkoxide 501 (here, pentaethoxy molybdenum (V)) including metal atoms ofthe first metal oxide, an organic compound 502 (here,5-diphenylamino-8-quinolinol) that gives a hole injecting ortransporting property to the composite material according to the presentinvention, and a stabilization agent 503 (here, ethyl acetoacetate) at aratio of 2:1:1 [unit: mol] in an appropriate organic solvent to preparea solution 504, and carrying out hydrolysis by adding water to obtain asol 505. In this case, as the organic solvent, for example,tetrahydrofran (THF), acetonitrile, dichloromethane, dichloroethane, anda mixed solvent of these can be used in addition to lower alcohols suchas methanol, ethanol, n-propanol, i-propanol, n-butanol, andsec-butanol. However, the organic solvent is not limited to these.

In addition, it is preferable that the amount of the organic compound502 be 0.1 mol or more and 1 mol or less with respect to 1 mol of themetal alkoxide 501.

It is to be noted that the stabilization agent 503 is added forpreventing precipitation from being produced due to rapid progress ofpolycondensation when water is added. However, the stabilization agent503 is not indispensable since the organic compound 502 can act also asa stabilization agent. When the organic compound 502 is small in amount(specifically, 0.5 mol or less with respect to 1 mol of the metalalkoxide 501), however, it is preferable to add the stabilization agent503 since the stabilization ability is impaired. As the stabilizationagent 503, weak chelating agents such as β-diketones, diamines, andaminoalcohols are preferable, and specifically, acethylacetone,benzoylacetone, ethylenediamine, monoethanolamine, and the like can becited in addition to ethyl acetoacetate shown in the formula (23).However, the stabilization agent 503 is not limited to these. Thestabilization agent 503 can exert an effect when the amount of thestabilization agent 503 is 0.5 mol or more with respect to 1 mol of themetal alkoxide 501. In addition, it is preferable that the additionamount of the stabilization agent 503 be 6 mol or less with respect to 1mol of the metal alkoxide 501 since the metal of the metal alkoxide 501is hexavalent or less.

It is preferable that the addition amount of the water that is used forthe hydrolysis be 2 mol or more and 6 mol ore less with respect to 1 molof the metal alkoxide 501 since the metal of the metal alkoxide 501 is adivalent to hexavalent metal. However, hydrolysis is not indispensable.

When a composite material to which a second metal oxide and a thirdmetal oxide are further added is manufactured as the composite material,a second metal alkoxide including the metal of the second metal oxideand a third metal alkoxide including the metal of the third metal oxidemay be added to the solution 504. In this case, the stabilization agentmentioned above may be further added appropriately. In addition, whensilicon oxide is applied as the third metal oxide, tetraalkoxysilane maybe used as the third metal alkoxide, and in this case, it is preferablethat the solution 504 be made acid or alkaline, more preferably, acid atpH 1 to 3.

The formula (24) shows a process of applying and baking the thusobtained sol 505 to obtain a composite material 506 according to thepresent invention. For the process, a method of applying the sol 505 ona base material by wet coating and baking the sol 505 at a temperatureof 100° C. or more but not exceeding 300° C. under atmospheric pressureor reduced pressure can be used. The baking may be performed either inthe atmosphere or in an inert gas (for example, nitrogen or argon). Inaddition, when a stabilization agent is used in the formula (23), it ispreferable to remove the stabilization agent by this baking.

Further, as shown in the formula (23), when a β-diketone (ethylacetoacetate in the formula (23)) is added as a stabilization agent,gelation may be conducted in such a way that the sol 505 is applied on abase material by wet coating, and then, irradiated with ultravioletlight of a wavelength overlapping with an ultraviolet absorptionspectrum of a state in which the β-diketone is bound to the metal atomas a ligand (a state in which ethyl acetoacetate is bound to molybdenumas a ligand in the case of the formula (23)) to dissociate theβ-diketone. After that, the composite material 506 according to thepresent invention can be obtained by baking in the same way as describedabove.

Further, when the hydrolysis in the formula (23) is not carried out, thesolution 504 may be directly applied on a base material by wet coating,dried, and then, hydrolysis may be carried out with water vapor. Afterthat, the composite material 506 according to the present invention canbe obtained by baking in the same way as described above.

As the wet coating described above, dip coating, spin coating, inkjet,and the like can be used here. However, the wet coating is not limitedto these.

Embodiment Mode 6

In the present embodiment, a method of manufacturing the compositematerial according to the present invention, which is described inEmbodiment Mode 1 or 2, by a sol-gel method utilizing peptization (alsoreferred to as deflocculation) will be described.

The following formulas (25) to (27) show a scheme of the method. In thepresent embodiment, a case of manufacturing the composite material(Embodiment Mode 1) using a molybdenum oxide skeleton as the first metaloxide skeleton and 5-diphenylamino-8-quinolinol as the organic compoundthat has a hole injecting or transporting property and is able to bebound to a molybdenum atom as a chelate ligand, from which themolybdenum oxide is able to accept electrons, will be described as anexample. The same basic principle is applied also to a case of usinganother metal oxide skeleton, a case of using a metal oxide skeletonhaving two or more kinds of metals, and a case of using another organiccompound.

Formula (25)

Formula (26)

Formula (27)

The formula (25) shows a method of dropping ammonia water to a solutionof a metal chloride 601 (here, molybdenum chloride (V)) including metalatoms of the first metal oxide to obtain a multinuclear precipitation602 of a metal hydroxide, and then, adding an acid such as acetic acidand refluxing (peptizing) the multinuclear precipitation 602 to obtain afirst Sol 603. An appropriate organic solvent may be appropriately addedto the first sol 603.

The formula (26) shows a pathway of adding, with respect to 1 mol of themetal (here, molybdenum) of the first sol 603 obtained in accordancewith the formula (25), 0.5 mol of an organic compound 604(5-diphenylamino-8-quinolinol) that gives a hole injecting ortransporting property to the composite material according to the presentinvention to obtain a second sol 605. An appropriate organic solvent mayappropriately be added to the second sol 605.

Further, it is preferable that the amount of the organic compound 604 be0.1 mol or more and 1 mol or less with respect to 1 mol of the metal inthe first sol 603.

When a composite material to which a second metal oxide and a thirdmetal oxide are further added is manufactured as the composite material,a sol including the metal of the second metal oxide and the metal of thethird metal oxide may be manufactured by peptization in the same way asthe first sol 603, and added to the second sol 605. Alternatively, asecond metal alkoxide including the metal of the second metal oxide anda third metal alkoxide including the metal of the third metal oxide maybe added to the second sol 605. In this case, a stabilization agent andwater may be further added appropriately. In addition, when siliconoxide is applied as the third metal oxide, tetraalkoxysilane may be usedas the third metal alkoxide, and in this case, it is preferable that thesecond sol 605 be made acid or alkaline, more preferably, acid at pH 1to 3.

The formula (27) shows a process of applying and baking the thusobtained second sol 605 to obtain a composite material 606 according tothe present invention. For the process, a method of applying the secondsol 605 on a base material by wet coating and baking the second sol 605at a temperature of 100° C. or more but not exceeding 300° C. underatmospheric pressure or reduced pressure can be used. The baking may beperformed either in the atmosphere or in an inert gas (for example,nitrogen or argon). In addition, when a stabilization agent is includedin the second sol 605, it is preferable to remove the stabilizationagent by this baking.

Further, when a stabilization agent is included in the second sol 605,gelation may be conducted in such a way that the second sol 605 isapplied on a base material by wet coating, and then, irradiated withultraviolet light of a wavelength overlapping with an ultravioletabsorption spectrum of a state in which the β-diketone as astabilization agent is bound to the metal atom as a ligand to dissociatethe β-diketone. After that, the composite material 606 according to thepresent invention can be obtained by baking in the same way as describedabove.

Further, when a metal alkoxide is included in the second sol 605, thesecond sol 605 may be applied on a base material by wet coating, dried,and then, hydrolysis may be carried out with water vapor. After that,the composite material 606 according to the present invention can beobtained by baking in the same way as described above.

As the wet coating described above, dip coating, spin coating, inkjet,and the like can be used here. However, the wet coating is not limitedto these.

Embodiment Mode 7

In the present embodiment, a method of manufacturing the compositematerial according to the present invention, which is described inEmbodiment Mode 3 or 4, by a sol-gel method using a metal alkoxide willbe described.

The following formulas (28) to (31) show a scheme of the method. In thepresent embodiment, a case of manufacturing the composite material(Embodiment Mode 3) using an aluminum oxide skeleton as the first metaloxide skeleton, 5-diphenylamino-8-quinolinol as the organic compoundthat has a hole injecting or transporting property and is able to bebound to an aluminum atom as a chelate ligand, and titanium oxide as thesecond metal oxide that exhibits an electron accepting property to theorganic compound will be described as an example. The same basicprinciple is applied also to a case of using another metal oxideskeleton, a case of using a metal oxide skeleton having two or morekinds of metals, and a case of using another organic compound.

Formula (28)

Formula (29)

Formula (30)

Formula (31)

The formula (28) shows a pathway of dissolving and reacting a metalalkoxide 701 (here, aluminum sec-butoxide) including metal atoms of thefirst metal oxide, an organic compound 702 (here,5-diphenylamino-8-quinolinol) that gives a hole injecting ortransporting property to the composite material according to the presentinvention, and a stabilization agent 703 (here, ethyl acetoacetate) at aratio of 2:1:1 [unit: mol] in an appropriate organic solvent to preparea solution 704, and carrying out hydrolysis by adding water to obtain afirst sol 705. In this case, as the organic solvent, for example, THF,acetonitrile, dichloromethane, dichloroethane, and a mixed solvent ofthese can be used in addition to lower alcohols such as methanol,ethanol, n-propanol, i-propanol, n-butanol, and sec-butanol. However,the organic solvent is not limited to these.

In addition, it is preferable that the amount of the organic compound702 be 0.1 mol or more and 1 mol or less with respect to 1 mol of themetal alkoxide 701.

It is to be noted that the stabilization agent 703 is added forpreventing precipitation from being produced due to rapid progress ofpolycondensation when water is added. However, the stabilization agent703 is not indispensable since the organic compound 702 can act also asa stabilization agent. When the organic compound 702 is small in amount(specifically, 0.5 mol or less with respect to 1 mol of the metalalkoxide 701), however, it is preferable to add the stabilization agent703 since the stabilization ability is impaired. As the stabilizationagent 703, weak chelating agents such as β-diketones, diamines, andaminoalcohols are preferable, and specifically, acethylacetone,benzoylacetone, ethylenediamine, monoethanolamine, and the like can becited in addition to ethyl acetoacetate shown in the formula (28).However, the stabilization agent 703 is not limited to these. Thestabilization agent 703 can exert an effect when the amount of thestabilization agent 703 is 0.5 mol or more with respect to 1 mol of themetal alkoxide 701. In addition, it is preferable that the additionamount of the stabilization agent 703 be 6 mol or less with respect to 1mol of the metal alkoxide 701 since the metal of the metal alkoxide 701is hexavalent or less.

It is preferable that the addition amount of the water that is used forthe hydrolysis be 2 mol or more and 6 mol or less with respect to 1 molof the metal alkoxide 701 since the metal of the metal alkoxide 701 is adivalent to hexavalent metal. However, hydrolysis is not indispensable.

The formula (29) shows a pathway of dissolving and reacting a metalalkoxide 706 (here, pentaethoxy molybdenum (V)) including metal atoms ofthe second metal oxide and a stabilization agent 707 (here, ethylacetoacetate) at a ratio of 1:1 [unit:mol] in an appropriate organicsolvent to prepare a solution 708, and carrying out hydrolysis by addingwater to obtain a sol 709. At this point, the same solvent as in thefirst sol 705 can be used as the organic solvent.

It is preferable that the addition amount of water that is used for thehydrolysis be 2 mol or more and 6 mol ore less with respect to 1 mol ofthe metal alkoxide 706 since the metal of the metal alkoxide706 is adivalent to hexavalent metal. However, hydrolysis is not indispensable.

It is to be noted that the stabilization agent 707 is not indispensablewhen the hydrolysis is not carried out. As the stabilization agent 707,the materials mentioned above can be used. The stabilization agent 707can exert an effect when the amount of the stabilization agent 707 is0.5 mol or more with respect to 1 mol of the metal alkoxide 706. Inaddition, it is preferable that the addition amount of the stabilizationagent 707 be 6 mol or less with respect to 1 mol of the metal alkoxide706 since the metal of the metal alkoxide 706 is hexavalent or less.

The formula (30) shows a pathway of mixing the first sol 705 and thesecond sol 709 to obtain a third sol 710. At this point, it-ispreferable to mix the first sol 705 and the second sol 709 so that theamount of the organic compound 702 is 0.1 or more and 10 mol or lesswith respect to 1 mol of the second metal alkoxide 706 in the third sol710. When a composite material to which a third metal oxide is furtheradded is manufactured as the composite material, a third metal alkoxideincluding the metal of the third metal oxide may be added to the thirdsol 710. In this case, the stabilization agent mentioned above may befurther added appropriately. In addition, when silicon oxide is appliedas the third metal oxide, tetraalkoxysilane may be used as the thirdmetal alkoxide, and in this case, it is preferable that a solutionincluding the third metal alkoxide be made acid or alkaline, morepreferably, acid at pH 1 to 3.

The formula (31) shows a process of applying and baking the thusobtained third sol 710. to obtain a composite material 711 according tothe present invention. For the process, a method of applying the thirdsol 710 on a base material by wet coating and baking the third sol 710at a temperature of 100° C. or more but not exceeding 300° C. underatmospheric pressure or reduced pressure can be used. The baking may beperformed either in the atmosphere or in an inert gas (for example,nitrogen or argon). In addition, when the third sol 710 includes astabilization agent, it is preferable to remove the stabilization agentby this baking.

Further, when a β-diketone (here, ethyl acetoacetate) is added as astabilization agent 703, gelation may be conducted in such a way thatthe third sol 710 is applied on a base material by wet coating, andthen, irradiated with ultraviolet light of a wavelength overlapping withan ultraviolet absorption spectrum of a state in which the β-diketone isbound to the metal atom as a ligand to dissociate the β-diketone. Afterthat, the composite material 711 according to the present invention canbe obtained by baking in the same way as described above.

Further, when the hydrolysis in the formula (28) or (29) is not carriedout, the third sol 710 may be directly applied on a base material by wetcoating, dried, and then, hydrolysis may be carried out with watervapor. After that, the composite material 711 according to the presentinvention can be obtained by baking in the same way as described above.

As the wet coating described above, dip coating, spin coating, inkjet,and the like can be used here. However, the wet coating is not limitedto these.

Embodiment Mode 8

In the present embodiment, a method of manufacturing the compositematerial according to the present invention, which is described inEmbodiment Mode 3 or 4, by a sol-gel method using a metal alkoxide andutilizing peptization will be described.

The following formulas (28) to (31) show a scheme of the method. In thepresent embodiment, a case of manufacturing the composite material(Embodiment Mode 3) using an aluminum oxide skeleton as the first metaloxide skeleton, 5-diphenylamino-8-quinolinol as the organic compoundthat has a hole injecting or transporting property and is able to bebound to an aluminum atom as a chelate ligand, and molybdenum oxide asthe second metal oxide that exhibits an electron accepting property tothe organic compound will be described as an example. The same basicprinciple is applied also to a case of using another metal oxideskeleton, a case of using a metal oxide skeleton having two or morekinds of metals, and a case of using another organic compound.

Formula (32)

Formula (33)

Formula (34)

Formula (35)

The formula (32) shows a pathway of dissolving and reacting a metalalkoxide 801 (here, aluminum sec-butoxide) including metal atoms of thefirst metal oxide, an organic compound 802 (here,5-diphenylamino-8-quinolinol) that gives a hole injecting ortransporting property to the composite material according to the presentinvention, and a stabilization agent 803 (here, ethyl acetoacetate) at aratio of 2:1:1 [unit:mol] in an appropriate organic solvent to prepare asolution 804, and carrying out hydrolysis by adding water to obtain afirst sol 805. In this case, as the organic solvent, for example, THF,acetonitrile, dichloromethane, dichloroethane, and a mixed solvent ofthese can be used in addition to lower alcohols such as methanol,ethanol, n-propanol, i-propanol, n-butanol, and sec-butanol. However,the organic solvent is not limited to these.

In addition, it is preferable that the amount of the organic compound802 be 0.1 mol or more and 1 mol or less with respect to 1 mol of themetal alkoxide 801.

It is to be noted that the stabilization agent 803 is added forpreventing precipitation from being produced due to rapid progress ofpolycondensation when water is added. However, the stabilization agent803 is not indispensable since the organic compound 802 can act also asa stabilization agent. When the organic compound 802 is small in amount(specifically, 0.5 mol or less with respect to 1 mol of the metalalkoxide 801), however, it is preferable to add the stabilization agent803 since the stabilization ability is impaired. As the stabilizationagent 803, weak chelating agents such as β-diketones, diamines, andaminoalcohols are preferable, and specifically, acethylacetone,benzoylacetone, ethylenediamine, monoethanolamine, and the like can becited in addition to ethyl acetoacetate shown in the formula (32).However, the stabilization agent 803 is not limited to these. Thestabilization agent 803 can exert an effect when the amount of thestabilization agent 803 is 0.5 mol or more with respect to 1 mol of themetal alkoxide 801. In addition, it is preferable that the additionamount of the stabilization agent 803 be 6 mol or less with respect to 1mol of the metal alkoxide 801 since the metal of the metal alkoxide 801is hexavalent or less.

It is preferable that the addition amount of the water that is used forthe hydrolysis be 2 mol or more and 6 mol ore less with respect to 1 molof the metal alkoxide 801 since the metal of the metal alkoxide 801 is adivalent to hexavalent metal. However, hydrolysis is not indispensable.

The formula (33) shows a method of dropping ammonia water to a solutionof a metal chloride 806 (here, molybdenum chloride (V)) including metalatoms of the second metal oxide to obtain a multinuclear precipitation807 of a metal hydroxide, and then, adding an acid such as acetic acidand refluxing (peptizing) the multinuclear precipitation 807 to obtain asecond sol 808. An appropriate organic solvent may be appropriatelyadded to the second sol 808.

The formula (34) shows a pathway of mixing the first sol 805 and thesecond sol 808 to obtain a third sol 809. At this point, it ispreferable to mix the first sol 805 and the second sol 809 so that theamount of the organic compound 802 is 0.1 or more and 10 mol or lesswith respect to 1 mol of the metal included in the second sol 808 in thethird sol 809. When a composite material to which a third metal oxide isfurther added is manufactured as the composite material, a third metalalkoxide including the metal of the third metal oxide may be added tothe third sol 809. In this case, the stabilization agent mentioned abovemay be further added appropriately. In addition, when silicon oxide isapplied as the third metal oxide, tetraalkoxysilane may be used as thethird metal alkoxide, and in this case, it is preferable that the thirdsol 809 be made acid or alkaline, more preferably, acid at pH 1 to 3.

The formula (35) shows a process of applying and baking the thusobtained third sol 809 to obtain a composite material 810 according tothe present invention. For the process, a method of applying the thirdsol 809 on a base material by wet coating and baking the third sol 809at a temperature of 100° C. or more but not exceeding 300° C. underatmospheric pressure or reduced pressure can be used. The baking may beperformed either in the atmosphere or in an inert gas (for example,nitrogen or argon). In addition, when the third sol 809 includes astabilization agent, it is preferable to remove the stabilization agentby this baking.

Further, when a β-diketone (here, ethyl acetoacetate) is added as astabilization agent, gelation may be conducted in such a way that thethird sol 809 is applied on a base material by wet coating, and then,irradiated with ultraviolet light of a wavelength overlapping with anultraviolet absorption spectrum of a state in which the β-diketone isbound to the metal atom as a ligand to dissociate the β-diketone. Afterthat, the composite material 810 according to the present invention canbe obtained by baking in the same way as described above.

Further, when the hydrolysis in the formula (32) is not carried out, thethird sol 809 may be directly applied on a base material by wet coating,dried, and then, hydrolysis may be carried out with water vapor. Afterthat, the composite material 810 according to the present invention canbe obtained by baking in the same way as described above.

As the wet coating described above, dip coating, spin coating, inkjet,and the like can be used here. However, the wet coating is not limitedto these.

Embodiment Mode 9

Subsequently, a light-emitting element according to the presentinvention will be described. The light-emitting element according to thepresent invention is a light-emitting element in which at least one ofrespective functional layers typified by an electron injecting layer, anelectron transporting layer, a hole injecting layer, and a holetransporting layer is formed by using any of the composite materialsaccording to the present invention, which are described in EmbodimentModes 1 to 4.

The light-emitting element according to the present invention includesnot only the layer formed by using the composite material describedabove but also at least a light-emitting layer including a luminescentmaterial, where the layers are interposed between a pair of electrodesconstituting the light-emitting element. Luminescence can be obtainedfrom the light-emitting layer by applying a voltage.

The light-emitting element according to the present invention, which hasthis structure, can be a heat-resistant light-emitting element since atleast one of respective functional layers typified by an electroninjecting layer, an electron transporting layer, a hole injecting layer,and a hole transporting layer is formed by the composite material havinga metal oxide skeleton according to the present invention, and can be alight-emitting element that can be driven with stability for a longperiod of time.

Further, the conductivity and carrier injecting or transporting propertyof the composite material are improved since the composite materialincludes an organic compound that has an electron injecting ortransporting property or a hole injecting or transporting property and ametal oxide that is able to accept electrons from the organic compoundor donate electrons to the organic compound.

Further, the light-emitting element according to the present inventioncan be a heat resistant light-emitting element, a light-emitting elementthat can be driven with stability for a long period of time, aheat-resistant light-emitting element that can be driven with stabilityfor a long period of time by the composite material including an organiccompound that has an electron injecting or transporting property or ahole injecting or transporting property and a metal oxide that is ableto accept electrons from the organic compound or donate electrons to theorganic compound, and it is possible to manufacturing a light-emittingelement having low power consumption.

It is to be noted that one of the functional layers of thelight-emitting element according to the present invention, which is notformed by using the composite material, may be formed further by usinganother material. Also in this case, when a layer that is most defectivein heat resistance and durability is formed by using the compositematerial, the heat resistance and the durability can be improved.

It is to be noted that the increase in driving voltage is less even whena light emitting element using the composite material according to thepresent invention for a functional layer is formed so that thefunctional layer has a thick film thickness. Therefore, the filmthickness of a functional layer between one of a pair of electrodes of alight-emitting element, which is formed first, and a light-emittinglayer of the light-emitting element can be made thick so that shortcircuit of the light-emitting element due to dust and the like can bereduced. When the film thickness is 100 nm or more, this defect can bereduced effectively.

Since the functional layer to be made thick includes the compositematerial including an organic compound that has an electron injecting ortransporting property or a hole injecting or transporting property and ametal oxide that is able to accept electrons from the organic compoundor donate electrons to the organic compound according to the presentinvention, the functional layer is improved in the conductivity and thecarrier injecting or transporting property, and thus, short circuit ofthe light-emitting element due to dust and the like can be reducedwithout increasing the driving voltage significantly, that is, withoutincreasing the power consumption significantly.

It is to be noted that any one of the functional layers typified by anelectron injecting layer, an electron transporting layer, a holeinjecting layer, and a hole transporting layer may be formed by usingany of composite materials or two or more functional layers thereof maybe formed by using the composite materials. Alternatively, all thefunctional layers may be formed by using the composite materials.Further, the light-emitting layer can be also formed by using acomposite material including an organic compound that is bound to ametal atom in a metal oxide skeleton as a chelate ligand. When thelight-emitting layer is formed by using the composite material, a moreheat-resistant light-emitting element that can be driven with morestability for a longer period of time can be manufactured. In this case,the light-emitting layer can be formed by applying an organic compoundthat produces luminescence by applying a voltage and a sol including amaterial for a metal oxide to the surface on which the light-emittinglayer is to be formed and baking the organic compound and the sol. Forexample, a light-emitting layer in which an organic compound thatproduces luminescence by applying a voltage is bound to a metal atom ina metal oxide skeleton as a chelate ligand can be formed. It is to benoted this sol is manufactured in accordance with the method ofmanufacturing the first sol 705 in Embodiment Mode 7 of the presentinvention, and applied and baked in accordance with the method ofapplying and baking the composite material according to the presentinvention. This makes it possible to manufacture a light-emitting layerhaving a metal oxide skeleton.

Subsequently, FIGS. 19A and 19B and FIGS. 20A and 20B show schematicdiagrams of examples of light-emitting element according to the presentinvention. In FIG. 19A, a first electrode 201 is formed on an insulatingsurface 200 such as a substrate, and further, a hole injecting and/ortransporting layer 202 formed by using the composite material accordingto the present invention (a layer shown by Reference numeral 202 may bedevided into double layers of a hole injecting layer and a holetransporting layer), a light-emitting layer 203, and an electroninjecting and/or transporting layer 204 formed by using the compositematerial according to the present invention (a layer shown by Referencenumeral 204 may be devided double layers of into a hole injecting layerand a hole transporting layer) are stacked in sequence thereon. Further,a second electrode 205 for a light-emitting element is formed thereon.When the light-emitting element is driven, luminescence can be obtainedby applying a voltage so that the first electrode 201 has a higherpotential than the second electrode 205 (that is, the first electrode201 serves as an-anode while the second electrode 205 serves ascathode).

The light-emitting layer 203 may be formed by evaporation or by using acomposite material including an organic compound that producesluminescence by applying a voltage and a metal oxide skeleton asdescribed above.

In this structure, both of the hole injecting and/or transporting layer202 and the electron injecting and/or transporting layer 204 arerespectively formed by using the composite materials according to thepresent invention. However, any layers may be formed by using thecomposite material according to the present invention.

Further, the layer, which is not formed by using the composite materialaccording to the present invention, may be formed by a known method suchas evaporation with the use of a known material.

The light-emitting element shown in FIG. 19A can be a heat-resistantlight-emitting element that can be driven with stability for a longperiod of time.

FIG. 19B is a schematic diagram of a light-emitting element that has ahole injecting and/or transporting layer 206 formed by making the holeinjecting and/or transporting layer 202 in FIG. 19A thicker. Since theother layers in FIG. 19B are the same as those in FIG. 19A, descriptionsthere of are omitted. A light-emitting element is formed by stackingultrathin films. When the first electrode 201 formed at the bottom has aconvex portion with a small curvature and a high height (considered tobe caused by dust or irregularity of a lower portion), the convexportion is not completely covered with the thin films, and the films arethus broken to cause a failure such as short circuit. On the other hand,when the films are formed to be thicker in order to prevent the failure,the light-emitting element has the disadvantage that the resistance isincreased to increase the driving voltage. However, since the compositematerial according to the present invention includes an organic compoundthat has an electron injecting or transporting property or a holeinjecting or transporting property and a metal oxide that is able toaccept electrons from the organic compound or donate electrons to theorganic compound, the conductivity of the composite material is high,and increase in the resistance can be thus suppressed even when a filmis made thicker. Further, the light-emitting element that has thestructure shown in FIG. 19B, which basically has the structure shown inFIG. 19A, is a heat-resistant light-emitting element that can be drivenwith stability for a long period of time. Accordingly, it is determinedthat the light-emitting element according to the present invention,which has the structure shown in FIG. 19B, is a heat resistantlight-emitting element that can be driven with stability for a longperiod of time and is less defective.

FIG. 20A shows an example in which a hole injecting and/or transportinglayer 207 formed by using the composite material according to thepresent invention is interposed between the electron injecting and/ortransporting layer 204 and the second electrode 205 in FIG. 19A. Thehole injecting and/or transporting layer 207 formed by using thecomposite material according to the present invention is formed by usinga composite material that uses an organic compound that has an excellenthole injecting or transporting property as the organic compound in thecomposite material and further includes a substance that is cable toaccept electrons from the organic compound, that is, by using a materialthat is used for a hole injecting layer or a hole transporting layerunder normal circumstances.

However, by stacking the electron injecting and/or transporting layer204 formed by using the composite material according to the presentinvention and the hole injecting and/or transporting layer 207 formed byusing the composite material according to the present invention insequence on the side of the electrode that functions as a cathode (thesecond electrode 205) on the basis of the light-emitting layer 203, whena voltage is applied, an electron generated in electron injecting and/ortransporting layer 204 formed by using the composite material accordingto the present invention is injected into the light-emitting layer 203while a hole generated in the hole injecting and/or transporting layer207 formed by using the composite material according to the presentinvention is injected into the electrode that functions as a cathode(the second electrode 205), and current thus flows so that luminescencecan be obtained.

Alternatively, when this structure is formed on the side of theelectrode that functions as an anode (the first electrode 201) on thebasis of the light-emitting layer 203, a layer formed by using thecomposite material according to the present invention, which can be usedas an electron injecting and/or transporting layer, and a layer formedby using the composite material according to the present invention,which can be used as a hole injecting and/or transporting layer, can bestacked in sequence in the same way. It is to be noted that thisstructure may be provided on the either or both sides of the electrodethat functions as a cathode (the second electrode 205) and the electrodethat electrode that functions as a cathode (the second electrode 205)and the electrode that functions as an anode (the first electrode 201)on the basis of the light-emitting layer 203.

In the case of the light-emitting element that has this structure,materials for the first electrode 201 and the second electrode 205 canbe selected without any regard for work function, and thus, moresuitable electrodes can be selected depending on structures such as areflective electrode and a transparent electrode.

FIG. 20B shows an example of a light-emitting element that is able toprovide white light emission, where a first light-emitting layer 208, aseparation layer 209, and a second light-emitting layer 210 are providedbetween the hole injecting and/or transporting layer 202 and theelectron injecting and/or transporting layer 204 in FIG. 19A. Whitelight emission can be obtained by forming the first light-emitting layer208 and the second light-emitting layer 210 with the use of materialsthat provide luminescent colors that have a relationship ofcomplementary colors with each other, such as red and blue-green.

The separation layer 209 can be formed by a hole transporting material,an electron transporting material, a bipolar material, a hole blockingmaterial, a carrier generating material, or the like, provided that theseparation layer 209 has a light-transmitting property. The separationlayer 209 is provided for the purpose of preventing either the firstlight-emitting layer 208 or the second light-emitting layer 210 fromemitting stronger light due to energy transfer. As long as thisphenomenon does not occur, it is not particularly necessary to providethe separation layer 209.

The light-emitting element that has the structure shown in FIG. 20B isable to provide white light emission, and is a heat-resistantlight-emitting element that can be driven with stability for a longperiod of time. This element can be preferably used for lighting.

Further, the present embodiment can be used in combination with theother embodiment as long as there is no discrepancy.

Embodiment Mode 10

In the present embodiment, a display device according to the presentinvention will be described while describing a method for manufacturingthe display device with reference to FIGS. 11A to 11E and FIGS. 12A to12C. It is to be noted the display device according to the presentinvention can be applied also to a passive-matrix display devicealthough an example of manufacturing an active-matrix display device isdescribed in the present embodiment.

First, after forming a first base insulating layer 51 a and a secondbase insulating layer 51 b over a substrate 50, a semiconductor layer isfurther formed on the second insulating layer 51 b (FIG. 11A).

As a material for the substrate 50, glass, quartz, plastic (such aspolyimide, acrylic, polyethylene terephthalate, polycarbonate,polyacrylate, or polyethersulfone), and the like can be used. Thesubstrate may be used after being polished by CMP or the like, ifnecessary. In the present embodiment, a glass substrate is used.

The first base insulating layer 51 a and the second base insulatinglayer 51 b are provided in order to prevent an element that has adamaging effect on characteristics of a semiconductor film, such as analkali metal or an alkaline earth metal contained in the substrate 50,from diffusing into the semiconductor layer. As materials for the firstand second base insulating layer 51 a and 51 b, silicon oxide, siliconnitride, silicon oxide containing nitrogen, silicon nitride containingoxygen, and the like can be used. In the present embodiment, the firstbase insulating layer 51 a and the second base insulating layer 51 b areformed by using silicon nitride, silicon oxide respectively. Although abase insulating layer is formed by the two layers of the first baseinsulating layer 51 a and the second insulating layer 51 b in thepresent embodiment, the base insulting layer may be formed by a singlelayer, or by a multilayer of two or more layers. Alternatively, it isnot necessary to provide the base insulating film when diffusions ofimpurities from the substrate are negligible.

The subsequently formed semiconductor layer is obtained by performinglaser crystallization of an amorphous silicon film in this embodiment.An amorphous silicon film is formed on the second base insulating layer51 b to have a film thickness of 25 to 100 nm (preferably, 30 to 60 nm).As a manufacturing method thereof, a known method such as sputtering,low pressure CVD, or plasma CVD can be used. Subsequently, heattreatment at 500° C. for one hour is performed for dehydrogenation.

Then, the amorphous silicon film is crystallized with the use of a laserirradiation system to form a crystalline silicon film. For the lasercrystallization in the present embodiment, an excimer laser is used, anemitted laser beam is processed to be a linear beam spot by using anoptical system, and the amorphous silicon film is irradiated with thelinear beam spot to be a crystalline silicon film, which is used as thesemiconductor layer.

As another method for crystallizing an amorphous silicon film, there arealso a method of performing crystallization only by heat treatment and amethod of performing crystallization by heat treatment with the use of acatalytic element that promotes crystallization. Nickel, iron,palladium, tin, lead, cobalt, platinum, copper, gold, and the like canbe used as the element that promotes crystallization. By using theelement, crystallization can be performed at a lower temperature in ashorter time, as compared with a case of performing crystallization onlyby heat treatment. Therefore, a glass substrate or the like is lessdamaged. In the case of performing crystallization only by heattreatment, a highly heat-resistant quartz substrate or the like may beused as the substrate 50.

Subsequently, doping with a small amount of impurity, so-called channeldoping, is performed to the semiconductor layer in order to control athreshold voltage, if necessary. The semiconductor layer is doped withan n-type or p-type impurity (phosphorus, boron, or the like) by iondoping or the like in order to obtain a required threshold voltage.

After that, as shown in FIG. 11A, the semiconductor layer is shapd intoa predetermined shape to obtain an island-shaped semiconductor layer 52.The semiconductor layer is shaped in such a way that a photoresist isapplied to the semiconductor layer, exposed to light to have apredetermined mask shape, and baked to form a resist mask on thesemiconductor layer, and etching is performed by using the mask.

Subsequently, a gate insulating layer 53 is formed to cover thesemiconductor layer 52. The gate insulating layer 53 of an insulatinglayer containing silicon is formed by plasma CVD or sputtering to have afilm thickness 40 to 150 nm. In the present embodiment, the gateinsulating layer 53 is formed by using silicon oxide.

Next, a gate electrode 54 is formed on the gate insulating layer 53. Thegate electrode 54 may be formed by using an element selected fromtantalum, tungsten, titanium, molybdenum, aluminum, copper, chromium,and niobium or using an alloy material or compound material mainlycontaining the element. Alternatively, a semiconductor film typified bya polycrystalline silicon film doped with an impurity element such asphosphorus may be used.

In the present embodiment, the gate electrode 54 is formed by a singlelayer. However, a laminated structure of two or more layers, forexample, tungsten for a lower layer and molybdenum for an upper layer,may be employed. Also when the gate electrode 54 is formed to have alaminated structure, the materials mentioned in the above paragraph arepreferably used. Further, the combination of the materials may beappropriately selected. The process for the gate electrode 54 isperformed by etching with the use of a mask using a photoresist.

Subsequently, with the gate electrode 54 as a mask, the semiconductorlayer 52 is doped with a high concentration of impurity. In this way, athin film transistor including the semiconductor layer 52, the gateinsulating layer 53, and the gate electrode 54 is formed.

It is to be noted that the manufacturing process of the thin filmtransistor 70 is not particularly limited, and may be appropriatelychanged so that a transistor that has a desired structure can bemanufactured.

In the present embodiment, a top-gate thin film transistor using acrystalline silicon film crystallized by using laser crystallization isused. However, a bottom-gate thin film transistor using an amorphoussemiconductor film can be used for a pixel portion. Silicon germanium aswell as silicon can be used for the amorphous semiconductor. In the caseof using silicon germanium, it is preferable that the concentration ofgermanium be approximately 0.01 to 4.5 atomic %.

In addition, a microcrystalline semiconductor (semi-amorphoussemiconductor) film in which a crystal grain of 0.5 to 20 nm can beobserved within an amorphous semiconductor may be used. A microcrystalin which a crystal grain of 0.5 to 20 nm can be observed is alsoreferred to as a so-called microcrystal (μc).

Semi-amorphous silicon (also referred to as SAS) that is asemi-amorphous semiconductor can be obtained by glow dischargedecomposition of a silicide gas. As the silicide gas, SiH₄ is typical,and in addition, Si₂H₆, SiH₂Cl₂, SiHCl₃, SiCl₄, SiF₄, and the like canalso be used. SAS can be formed easily by diluting the silicide gas withhydrogen or with hydrogen and one or more rare gas elements selectedfrom helium, argon, krypton, and neon. It is preferable to dilute thesilicide gas so that the dilution ratio ranges from 10 to 1000 times.Reaction production of a film by glow discharge decomposition may beperformed under a pressure in the range of 0.1 to 133 Pa. Ahigh-frequency power of 1 to 120 MHz, preferably 13 to 60 MHz, may besupplied to generate glow discharge. It is preferable that the substrateheating temperature be 300° C. or less, and a substrate heatingtemperature of 100 to 250° C. is preferred.

The thus formed SAS has a raman spectrum shifted to a lower frequencyside than 520 cm⁻¹. In X-ray diffraction, diffraction peaks of (111) and(220) that are considered due to a crystal lattice of silicon areobserved. The SAS contains at least 1 atomic % or more of hydrogen orhalogen to terminate a dangling bond. It is desirable that theconcentration of an atmospheric component impurity such as oxygen,nitrogen, or carbon is 1×10²⁰/cm³ or less as an impurity element in thefilm, and particularly, the oxygen concentration is made to be5'10¹⁹/cm³ or less, preferably 1×10¹⁹/cm³ or less. When the SAS is usedfor a TFT, the field effect mobility thereof is μ=1 to 10 cm²/Vsec.

In addition, this SAS may be further crystallized with a laser.

Subsequently, an insulating film (hydrogenation film) 59 is formed byusing silicon nitride to cover the gate electrode 54 and the gateinsulating layer 53. After forming the insulating film (hydrogenationfilm) 59, heating is performed at 480° C. for about an hour to activatethe impurity elements and hydrogenate the semiconductor layer 52.

Subsequently, a first interlayer insulating layer 60 is formed to coverthe insulating film (hydrogenation film) 59. As a material for formingthe first interlayer insulating layer 60, silicon oxide, acrylic,polyimide, siloxane, a low-k material, and the like are preferably used.In the present embodiment, silicon oxide is formed as the firstinterlayer insulating layer 60 (FIG. 11B).

Next, contact holes reaching the semiconductor layer are formed. Thecontact holes can be formed by etching with the use of a resist maskuntil exposing the semiconductor layer 52, and can be formed by eitherwet etching or dry etching. It is to be noted that etching may beperformed once or divided into more than once according to thecondition. When etching is performed more than once, both wet etchingand dry etching may be used (FIG. 11C).

Then, a conductive layer is formed to cover the contact holes and theinterlayer insulating layer 60. The conductive layer is processed into apredetermined shape to form a connecting portion 61 a, a wiring 61 b,and the like. This wiring may be a single layer of aluminum, copper, analloy of aluminum, carbon, and nickel, an alloy of aluminum, carbon, andmolybdenum, or the like. However, a laminated structure of molybdenum,aluminum, and molybdenum formed in the order of formation, a laminatedstructure of titanium, aluminum, titanium in the order of formation, anda laminated structure of titanium, titanium nitride, aluminum, andtitanium in the order of formation may be employed (FIG. 11D).

After that, a second interlayer insulating layer 63 is formed to coverthe connection portion 61 a, the wiring 61 b, and the first interlayerinsulating layer 60. As a material for the second interlayer insulatinglayer 63, a self-flatness coating film such as acrylic, polyimide, orsiloxane are preferably used. In the present embodiment, siloxane isused for the second interlayer insulating layer 63 (FIG. 11E).

Subsequently, an insulating layer may be formed on the second interlayerinsulating layer 63 with the use of silicon nitride or the like. Thisinsulating layer is formed for preventing the second interlayerinsulating layer 63 from being etched more than necessary in etching apixel electrode later. Therefore, when the ratio between the etchingrates for the pixel electrode and the second interlayer insulating layer63 is large enough, it is not particularly necessary to provide theinsulating layer. Subsequently, a contact hole reaching the connectingportion 61 a through the second interlayer insulating layer 63.

Then, after forming a light-transmitting conductive layer to cover thecontact hole and the second interlayer insulating layer 63 (or theinsulating layer), the light-transmitting conductive layer is processedto form a first electrode 64 for a thin film light-emitting element,where the first electrode 64 is electrically connected to the connectingportion 61 a.

For the first electrode 64, a conductive film can be formed by using amaterial, for example, conductive metals such as aluminum (Al), silver(Ag), gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium(Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium(Pd), lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), strontium(Sr), and titanium (Ti), alloys of these metals, a nitiride (TiN) of ametal material, or metal oxides such as indium tin oxide (ITO), ITOcontaining silicon (ITSO), IZO (indium zinic oxide) of indium oxidemixed with zinic oxide (ZnO).

In addition, the electrode from which luminescence is extracted isformed by using a light-transmitting conductive film, and an ultrathinfilm of a metal such as Al or Ag is used besides metal oxides such asITO, ITSO, and IZO. In the case of extracting luminescence from a secondelectrode 67 to be formed later, a material that has a high reflectivity(such as Al and Ag) can be used for the first electrode 64. In thepresent embodiment, ITSO is used for the first electrode 64 (FIG. 12A).

Next, an insulating film including an organic material or an inorganicmaterial is formed to cover the second interlayer insulating layer 63(or the insulating layer) and the first electrode 64. Subsequently, theinsulating layer is processed so that a portion of the first electrode64 is exposed, and a partition 65 is thus formed. As a material for thepartition 65, a photosensitive organic material (such as acrylic andpolyimide) is preferably used. However, a non-photosensitive organicmaterial or inorganic material may be used for forming the partition 65.Further, as a material for the partition 65, a black pigment or dye suchas black titanium or carbon nitride may be dispersed with the use of adispersant to make the partition 65 black like a black matrix. It ispreferable that an edge surface of the partition 65 toward the firstelectrode 64 have a curvature and a tapered shape in which the curvatureis continuously changing (FIG. 12B).

Next, a hole injecting layer is manufactured by using a compositematerial according to the present invention to cover the first electrode64, which is not covered with the partition 65. Specifically, acomposite material that includes a transition metal oxide and an organiccompound having an arylamine skeleton is used. This hole injecting layermay be manufactured in accordance with the method described in any ofEmbodimentModes 5 to 8, and inkjet is preferably used for coating. Next,a light-emitting layer is manufactured by a known method. Coating isperformed by inkjet in the same way. Subsequently, an electron injectinglayer is manufactured by using a composite material according to thepresent invention. For example, a composite material that includes analkali metal oxide and an organic compound having a pyridine skeleton isused. This electron injecting layer may be manufactured in accordancewith the method described in any of Embodiment Modes 5 to 8, and inkjetis preferably used for coating.

Subsequently, the second electrode 67 is formed to cover alight-emitting laminated body 66 (also referred to as anelectroluminescence layer) which consists of the hole injecting layer,the light-emitting layer, the electron injecting layer, and the like. Inthis way, a light-emitting element 93 formed by sandwiching thelight-emitting laminated body 66 including the light-emitting layerbetween the first electrode 64 and the second electrode 67 can bemanufactured, and luminescence can be obtained by applying a higherpotential to the first electrode 64 than to the second electrode 67. Asan electrode material to be used for forming the second electrode 67,the same materials as for the first electrode 64 can be used. In thepresent embodiment, aluminum is used for the second electrode.

The light-emitting element, which has the structure described above, isa heat-resistant and durable panels and modules since the compositematerial having the metal oxide skeleton is used for light-emittingelements. Further, since the composite material according to the presentinvention includes an organic compound that has an electron injecting ortransporting property or a hole injecting or transporting property and ametal oxide that is able to accept electrons from the organic compoundor donate electrons to the organic compound, light-emitting elementsthat have an improved electron injecting or transporting property or animproved hole injecting or transporting property and further hasimproved conductivity can be provided.

Further, when the functional layer on the first electrode is formed tobe 100 nm or more in thickness with the use of the composite materialthat has an improved electron injecting or transporting property or animproved hole injecting or transporting property and further hasimproved conductivity, occurrence of defects due to dust and the like onthe first electrode can be reduced without causing a significantincrease in the driving voltage.

In addition, the hole injecting layer is formed on the first electrode64 in the present embodiment. However, an electron injecting layer maybe provided on the first electrode 64 to have a reversed laminatedstructure. In this case, luminescence can be obtained by making avoltage that is applied to the first electrode 64 lower than a potentialthat is applied to the second 67.

After that, a silicon oxide film containing nitrogen is formed by plasmaCVD as a first passivation film by plasma CVD. In the case of using asilicon oxide film containing nitrogen, a silicon oxynitride film thatis manufactured by using SiH₄, N₂O, and NH₃, a silicon oxynitride filmthat is manufactured by using SiH₄ and N₂O, or a silicon oxynitride filmthat is manufactured by using gas of SiH₄ and N₂O diluted with Ar may beformed by plasma CVD. Naturally, the structure of the first passivationfilm is not limited to a single layer structure. The first passivationfilm may have a single layer structure or laminated structure usinganother insulating layer including silicon. In addition, a multilayerfilm of a carbon nitride film and a silicon nitride film, a multilayerfilm of a styrene polymer, a silicon nitride film, or a diamond likecarbon film may be formed instead of the silicon oxide film containingnitrogen.

Subsequently, sealing of a display portion is performed to protect thelight-emitting element 93 from materials, such as water, that acceleratedeterioration. In the case of using an opposed substrate for sealing,the opposed substrate is attached with the use of a sealing material ofinsulation so that an external connecting portion is exposed. The spacebetween the opposed substrate and the element substrate may be filledwith an inert gas such as dried nitrogen, or the sealing material may beapplied to the whole surface of a pixel portion to attach the opposedsubstrate. It is preferable to use an ultraviolet curing resin or thelike for the sealing material. The sealing material may be mixed with adrying agent or particles for keeping a gap between the substratesconstant. Then, a light-emitting device is completed by attaching aflexible printed circuit to the external connecting portion.

Examples of the structure of the thus manufactured display device willbe described with reference to FIGS. 13A and 13B. It is to be noted thatthe same reference numeral is assigned to portions that carry out thesame function even when the shapes of the portions are different fromeach other, and the description there of can be omitted. In the presentembodiment, the thin film transistor 70 that has an LDD structure isconnected to the light-emitting element 93 via the connecting potion 61a.

FIG. 13A shows a structure in which the first electrode 64 is formed byusing a light-transmitting conductive film, and light emitted from thelight-emitting laminated body 66 is extracted from the substrate 50side. Further, reference numeral 94 denotes an opposed substrate, whichis attached to the substrate 50 with the use of a sealing material orthe like after the light-emitting element 93 is formed. Alight-transmitting resin 88 or the like is provided between the opposedsubstrate 94 and the light-emitting element 93 for sealing so that thelight-emitting element 93 can be prevented from being deteriorated dueto moisture. In addition, it is preferable that the resin 88 behygroscopic. Further, it is more preferable to disperse a highlylight-transmitting drying agent 89 in the resin 88 since the effect ofmoisture can be further suppressed.

FIG. 13B shows a structure in which both the first electrode 64 and thesecond electrode 67 are each formed by a light-transmitting conductivefilm, and light can be extracted from both the substrate 50 and theopposed substrate 94. Further, in this structure, the screen can beprevented from being seen through by providing polarization plates 90 onthe outer sides of the substrate 50 and the opposed substrate 94, andthe visibility is thus improved. On the outer sides of the polarizationplates 90, protective films 91 are preferably provided.

It is to be noted that either an analog video signal or a digital videosignal may be used for the display device according to the presentinvention, which has a display function. In the case of a digital videosignal, the video signal uses either voltage or current. When alight-emitting element emits light, a video signal to be input to thepixel is either a constant-voltage signal or a constant-current voltage,and either the voltage that is applied to the light-emitting element orthe current that flows in the light-emitting element is constant in thecase of the constant-voltage signal. Either the voltage that is appliedto the light-emitting element or the current that flows in thelight-emitting element is constant in the case of the constant-currentsignal. The driving in which the voltage that is applied to thelight-emitting element is constant is referred to as constant voltagedriving, and the driving in which the current that flows in thelight-emitting element is constant is referred to as constant-currentdriving. In the constant-current driving, a constant current flowsregardless of change in the resistance of the light-emitting element.Any of the driving methods described above may be used For thelight-emitting display device according to the present invention.

The present embodiment can be used appropriately in combination with theother embodiments.

Embodiment Mode 11

In the present embodiment, the appearance of a panel of a light-emittingdevice that corresponds to one embodiment of the present invention willbe described with reference to FIGS. 14A and 14B. FIG. 14A is a top viewof a panel in which transistors 4008 and 4010 and a light-emittingelement 4011 that are formed over a substrate 4001 are sealed with asealing agent 4005 between the substrate 4001 and an opposed substrate4006. FIG. 14B corresponds to a cross-sectional view of FIG. 14A. Thestructure of the light-emitting element 4011 in the panel has thestructure described in Embodiment Mode 9.

The sealing agent 4005 is provided so as to surround a pixel portion4002, a signal line driver circuit 4003, and a scan line driver circuit4004 that are provided over the substrate 4001. Further, the opposedsubstrate 4006 is provided over the pixel portion 4002, the signal linedriver circuit 4003, and the scan line driver circuit 4004. Accordingly,the pixel portion 4002, the signal line driver circuit 4003, and thescan line driver circuit 4004 are sealed, together with a filling agent4007, with the substrate 4001, the sealing agent 4005, and the opposingsubstrate 4006.

Further, each of the pixel portion 4002, the signal line driver circuit4003, and the scan line driver circuit 4004 over the substrate 4001 hasa plurality of thin film transistors. In FIG. 14B, the thin filmtransistor 4008 included in the signal line driver circuit 4003 and thethin film transistor 4010 included in the pixel portion 4002 are shown.

Furtherer, the light-emitting element 4011 is electrically connected tothe thin film transistor 4010.

Further, a leading wiring 4014 corresponds to a wiring for supplyingsignals or a power supply voltage to the pixel portion 4002, the signaldriver circuit 4003, and the scan line driver circuit 4004. The leadwiring 4014 is connected to a connecting terminal 4016 via leadingwirings 4015 a and 4015 b. The connecting terminal 4016 is electricallyconnected to a terminal of a flexible printed circuit (FPC) 4018 via ananisotropic conductive film 4019.

As the filling agent 4007, ultraviolet curing resins and thermal curingresin can be used besides inert gases such as nitrogen or argon, andpolyvinylchloride, acrylic, polyimide, epoxy resin, silicon resin,polyvinyl butylal, or ethylene vinylene acetate can be used.

It is to be noted that a panel in which a pixel portion that has alight-emitting element is formed and a module in which an IC is mountedon the panel are included in the category of the display deviceaccording to the present invention.

Panels and modules that have the structure described in the presentembodiment are heat-resistant and durable panels and modules since thecomposite material having the metal oxide skeleton is used forlight-emitting elements. Further, since the composite material accordingto the present invention includes an organic compound that has anelectron injecting or transporting property or a hole injecting ortransporting property and a metal oxide that is able to accept electronsfrom the organic compound or donate electrons to the organic compound,panels and modules that have an improved electron injecting ortransporting property or an improved hole injecting or transportingproperty and further has improved conductivity can be provided.

Further, when the functional layer on the first electrode is formed tobe 100 nm or more in thickness with the use of the composite materialthat has an improved electron injecting or transporting property or animproved hole injecting or transporting property and further hasimproved conductivity, occurrence of defects due to dust and the like onthe first electrode can be reduced without causing a significantincrease in the driving voltage.

The present embodiment can be used appropriately in combination with theother embodiments.

Embodiment Mode 12

Electronic devices according to the present invention, which are eachmounted with a module like the example shown in Embodiment Mode 11,include a video camera, a digital camera, a goggle-type display (headmount display), a navigation system, a sound reproduction device (a caraudio component or the like), a computer, a game machine, a personaldigital assistance (a mobile computer, a cellular phone, a portable gamemachine, an electronic book, or the like), and an image reproductiondevice equipped with a recording medium (specifically, a device equippedwith a display, which can reproduce a recording medium such as a DigitalVersatile Disc (DVD) and display the image). Specific examples of theseelectronic devices are shown in FIGS. 15A to 15E.

FIG. 15A is a light-emitting display device, to which a television set,a monitor of a personal computer, or the like corresponds, include aframe body 2001, a display portion 2003, a speaker portion 2004, and thelike. Since the display portion 2003 is superior in heat resistance andcan be driven with stability for a long period of time, thelight-emitting display device according to the present invention is alight-emitting display device with high reliability. A pixel portion ispreferably provided with a polarization plate or a circularlypolarization plate in order to enhance the contrast. For example, it ispreferable to provide films in the order corresponding to a ¼λ plate, a½λ plate, and a polarization plate over a sealing substrate. Further, ananti-reflective film may be provided over the polarization plate.

FIG. 15B is a cellular phone, which includes a main body 2101, a framebody 2102, a display portion 2103, a sound input portion 2104, a soundoutput portion 2105, an operation key 2106, an antenna 2108, and thelike. Since the display portion 2103 is superior in heat resistance andcan be driven with stability for a long period of time, the cellularphone according to the present invention is a cellular phone with highreliability.

FIG. 15C is a computer, which includes a main body 2201, a frame body2202, a display portion 2203, a keyboard 2204, an external connectionport 2205, a pointing mouse 2206, and the like. Since the displayportion 2203 is superior in heat resistance and can be driven withstability for a long period of time, the computer according to thepresent invention is a computer with high reliability. In FIG. 15C, alaptop computer is shown as an example. However, the present inventioncan be applied to a desktop computer and the like.

FIG. 15D is a mobile computer, which includes a main body 2301, adisplay portion 2302, a switch 2303, an operation key 2304, an infraredport 2305, and the like. Since the display portion 2303 is superior inheat resistance and can be driven with stability for a long period oftime, the mobile computer according to the present invention is a mobilecomputer with high reliability.

FIG. 15E is a portable game machine, which includes a frame body 2401, adisplay portion 2402, a speaker portion 2403, operation keys 2404, arecording medium insert portion 2405, and the like. Since alight-emitting element in the display portion 2402 is superior in heatresistance and can be driven with stability for a long period of time,the portable game machine according to the present invention is aportable game machine with high reliability.

As described above, the present invention is capable of quite wideapplication, and can be thus used for electronic devices in all fields.

Embodiment Mode 13

FIGS. 16A to 16C respectively show examples of bottom-emission,dual-emission (that is, both-emission of bottom-emission andtop-emission), and top-emission devices. Each of FIGS. 16A and 16B showsa structure for the case of forming a first interlayer insulating layer63 in FIG. 16C with the use of a self-flatness material and forming awiring that is connected to a thin film transistor 70 and a firstelectrode 64 for a light-emitting element on the same interlayerinsulating layer. In FIG. 16A, only the first electrode 64 for thelight-emitting element is formed by using a light-transmitting materialto provide a bottom-emission structure in which light is emitted towardthe bottom of the light-emitting device. In the case of FIG. 16B, abottom-emission light-emitting display device that is able to extractlight from the both sides as shown in FIG. 16B can be obtained by usinga light-transmitting material such as ITO, ITSO, or IZO also for asecond electrode 67. It is to be noted that a material such as aluminumor silver, which is not light-transmitting in a thick film, gets to havea light-transmitting property when the thickness is made thinner.Therefore, also when the second electrode 67 is formed by using a filmof aluminum or silver that is thin enough to have a light-transmittingproperty, a dual-emission device can be obtained.

Embodiment Mode 14

In the present embodiment, a pixel circuit and a protection circuit thatare included in the panel or module described in Embodiment Mode 11 andoperations thereof will be described. It is to be noted that thecross-sectional views shown in FIGS. 11A to 11E and FIGS. 12A to 12Ccorrespond to cross-sectional views of a driving TFT 1403 and alight-emitting element 1405.

In the pixel shown in FIG. 17A, a signal line 1410, power supply lines1411 and 1412 are arranged in a column direction, and a scan line 1414is arranged in a row direction. The pixel also includes a switching TFT1401, a driving TFT 1403, a current controlling TFT 1404, a capacitor1402 and a light-emitting element 1405.

The pixel shown in FIG. 17C, which basically has the same structure asthe pixel shown in FIG. 17A, is different only in that a gate electrodeof a TFT 1403 is connected to a power supply line 1412 arranged in a rowdirection. Namely, each of FIGS. 17A and 17C illustrates the sameequivalent circuit diagram. However, when the case of arranging thepower supply line 1412 in the column direction (FIG. 17A) is compared tothe case of arranging the power supply line 1412 in the row direction(FIG. 17C), each of the power supply lines is formed by using aconductive film of a different layer. In the present embodiment,attention is given to the wiring connected to the gate electrode of eachdriving TFT 1403, and FIGS. 17A and 17C are separately illustrated toindicate that the layers for forming these wirings are different fromeach other.

In each of the pixels shown in FIGS. 17A and 17C, the TFTs 1403 and 1404are connected in series. It is preferable that the channel length L(1403) and channel width W (1403) of the TFT 1403 and the channel widthL (1404) and channel width W (1404) of the TFT 1404 satisfy L (1403)/W(1403): L (1404)/W (1404)=5 to 6000:1.

It is to be noted that the TFT 1403 operates in the saturation regionand functions to control a current value that is applied to thelight-emitting element 1405 while the TFT 1404 operates in the linearregion and functions to control current supply to the light-emittingelement 1405. Both of the TFTs preferably have the same conductivitytype in the light of the manufacturing steps, and are formed asN-channel TFTs in the present embodiment. For the TFT 1403, not only anenhancement mode TFT but also a depletion mode TFT may be used.According to the invention, which has the structure described above, theTFT 1404 operates in the linear region. Therefore, slight fluctuation inVgs of the TFT 1404 has no influence on a current value that is appliedto the light-emitting element 1405. Namely, the current value that isapplied to the light-emitting element 1405 can be determined by the TFT1403, which operates in the saturation region. The structure describedabove makes it possible to improve luminance unevenness oflight-emitting elements due to variations in characteristics of TFTs sothat a display device with enhanced image quality can be provided.

In each of the pixels shown in FIGS. 17A to 17D, the TFT 1401 controlsinput of a video signal to the pixel. When the TFT 1401 is turned ON, avideo signal is input to the pixel. Then, the voltage of the videosignal is held in the capacitor 1402. Although each of FIGS. 17A and 17Cillustrates a structure in which the capacitor 1402 is provided, theinvention is not limited to this. The capacitor 1402 may be omitted whena gate capacitance or the like can cover the capacitor for holding avideo signal.

The pixel shown in FIG. 17B, which basically has the same pixelstructure as FIG. 17A, is different only in that a TFT 1406 and a scanline 1415 are additionally provided. Similarly, the pixel shown in FIG.17D, which basically has the same pixel structure as FIG. 17C, isdifferent only in that the TFT 1406 and a scan line 1415 areadditionally provided.

The switching (ON/OFF) of the TFT 1406 is controlled by the scan line1415 provided additionally. When the TFT 1406 is turned ON, a chargeheld in the capacitor 1402 is discharged to turn OFF the TFT 1404.Namely, the arrangement of the TFT 1406 makes it possible to bring thelight-emitting element 1405 forcibly into a state where no current flowsthereto. Therefore, the TFT 1406 can be referred to as an erasing TFT.Thus, in the structures shown in FIGS. 17B and 17D, an emission periodcan be started simultaneously with or immediately after a writing periodwithout waiting for completion of writing signals to all pixels, andthus, the duty ratio an be improved.

In the pixel shown in FIG. 17E, a signal line 1410 and a power supplyline 1411 are arranged in a column direction, and a scan line 1414 isarranged in a row direction. The pixel also includes a switching TFT1401, a driving TFT 1403, a capacitor 1402 and a light-emitting element1405. The pixel shown in FIG. 17F, which basically has he same pixelstructure as FIG. 17E, is different only in that a TFT 1406 and a scanline 1415 are additionally provided. Also in the structure shown in FIG.17F, the arrangement of the TFT 1406 makes it possible to improve theduty ratio.

As described above, various pixel circuits can be employed. Inparticular, in the case of forming a thin film transistor by using anamorphous semiconductor film, it is preferable to make a semiconductorfilm for the driving TFT 1403 larger. Therefore, for the pixel circuitdescribed above, it is preferable to employ a top emission type in whichlight from a light-emitting element is emitted from a sealing substrateside.

This active-matrix light-emitting device can be driven at a low voltagewhen the pixel density is increased since a TFT is provided in eachpixel, and is thus considered to be advantageous.

In the present embodiment, an active-matrix light-emitting device inwhich a TFT is provided for each pixel is described. However, apassive-matrix light-emitting device in which a TFT is provided for eachcolumn can be also formed. The passive-matrix light-emitting device hasa high aperture ratio since a TFT is not provided for each pixel. In thecase of a light-emitting device in which luminescence is emitted to theboth sides of a light-emitting element, the transmittance is increasedwhen a passive-matrix light-emitting device is used.

A display device according to the present invention, which furtherincludes a pixel circuit like these, can be a light-emitting device thathas each of the features described above while a material that issuitable for the structure and required performance of a light-emittingelement can be used for an electrode of the light-emitting elementincluded in the display device.

Subsequently, a case of providing diodes as protection circuits for ascan line and a signal line will be described with reference to theequivalent circuit shown in FIG. 17E.

In FIG. 18, switching TFTs 1401 and 1403 a capacitor 1402, and alight-emitting element 1405 are provided in a pixel portion 1500. For asignal line 1410, diodes 1561 and 1562 are provided. The diodes 1561 and1562 are manufactured in accordance with the embodiment described abovein the same way as the switching TFTs 1401 and 1403, and each of thediodes 1561 and 1562 includes a gate electrode, a semiconductor layer, asource electrode, and a drain electrode. Each of the diodes 1561 and1562 operates as a diode by connecting the gate electrode to the drainelectrode or the source electrode.

Common potential lines 1554 and 1555 that are respectively connected tothe diodes 1561 and 1562 are formed by the same layer as the gateelectrode. Accordingly, in order to be connected to the source electrodeor drain electrode of each diode, it is necessary to form contact holesin a gate insulating layer.

Diodes that are provided for a scan line 1414 have the same structure.

As described above, a protective diode that is provided for an inputstate can be formed at the same time according to the present invention.It is to be noted that the position in which the protection diode isformed is not limited to this, and the protection circuit can beprovided between a driver circuit and a pixel.

A display device according to the present invention, which has thisprotection circuit, is superior in heat resistance and can be drivenwith stability for a long period of time, and thus has high reliability.The reliability of the display device can be further enhanced byincluding the structure described above.

Embodiment

In the present example, an example of manufacturing the compositematerial according to the present invention will be specificallyexplained.

<<Manufacturing Sample of Example>>

[1. Preparation of Sol]

First, in a glove box in which the concentration of water is kept a fewppm or so, 0.156 g (0.50 mmol) of 5-diphenylamino-8-quinolinol(abbreviation: DPAq) was dissolved, and 0.122 g (0.50 mmol) of vanadiumtri-iso-propoxide oxide was dropped. Next, 0.065 g (0.50 mmol) of ethylacetoacetate was dropped as a stabilization agent, and stirring wascarried out all night to obtain a sol.

[2. Manufacturing Composite Material According to the Present Invention]

Further, while the obtained sol was dropped on a quartz substratethrough a filter of 0.45 μm, spin coating was carried out underconditions of 200 rpm for 2 seconds, and then, 3000 rpm for 70 seconds.Next, the spin-coated substrate and a beaker with pure water put thereinwere put in an electric furnace, and heated at 40° C. for 2 hours tocarry out hydrolysis with water vapor. Further, the beaker with purewater put therein was taken out from the furnace, and the compositematerial according to the present invention was obtained by baking at120° C. for 1.5 hours while reducing the pressure in the furnace by arotary pump. In the composite material of the present example, the metaloxide skeleton is a vanadium oxide skeleton, and the organic compoundthat is bound to the metal of the metal oxide skeleton by forming achelate is DPAq.

<<Manufacturing Comparative Sample>>

For comparison, a sol excluding DPAq from the sol for the exampledescribed above was prepared, and applied to a quartz substrate andbaked under the same conditions mentioned above to manufacture acomparative sample. Namely, the comparative sample is a thin film ofvanadium oxide since ethyl acetoacetate as a stabilization agent wasduring the baking.

<<Experimental Result>>

A spectrophotometer (from Hitachi, Ltd., U-400) was used to measureultraviolet-visible-infrared absorption spectra of the sample of thepresent example and the comparative sample, which were manufactured asdescribed above. FIG. 21A shows the result. Further, FIG. 21B shows anenlarged view of the spectra from the visible region to thenear-infrared region (500 to 2000 nm).

As shown in FIGS. 21A and 21B, it is determined that new absorption isobserved around 480 nm (a in the figure) and around 1050 nm (b in thefigure) in the spectrum of the sample of the present example. Since theabsorption around 480 nm is observed when DPAq and an ion of a metalsuch as Ti or Al form a complex, the absorption is considered to beabsorption due to a chelate produced by DPAq being bound to vanadium. Onthe other hand, the absorption around 1050 nm in the near infrared is anabsorption band that is observed normally in a charge transfer complex(an electron donor-accepter complex), which suggests that chargetransfer is carried out between DPAq and vanadium oxide. Since thediphenylamino group of DPAq normally has a high electron donatingproperty, it is believed that DPAq and vanadium oxide are respectivelyan electron acceptor and an electron donor.

Further, in a sol-gel method, it is known that an oxide skeleton (a bondof metal-oxygen-metal) is formed by hydrolysis and baking. Namely,vanadium tri-iso-propoxide oxide forms a vanadium oxide skeleton.Accordingly, the example described above shows that it is possible tomanufacture the composite material according to the present invention,including the metal oxide (vanadium oxide) skeleton and the organiccompound (DPAq) that is bound to the metal atom (vanadium atom) of themetal oxide skeleton by forming a chelate, where the metal oxideexhibits an electron accepting property to the organic compound.

Although the present invention has been fully described by way ofexample with reference to the accompanying drawings, it is to beunderstood that various changes and modifications will be apparent tothose skilled in the art. Therefore, unless such changes andmodifications depart from the scope of the present invention hereinafterdefined, they should be construed as being included therein.

1. A composite material comprising: a metal oxide skeleton comprising ametal atom; and an organic compound that is bound to the metal atom byforming a chelate, wherein the metal oxide exhibits an electronaccepting property to the organic compound.
 2. The composite materialaccording to claim 1, wherein the organic compound is an organiccompound having an arylamine skeleton.
 3. The composite materialaccording to claim 1, wherein the metal atom is a transition metal. 4.The composite material according to claim 1, wherein the metal atom isone or more of titanium, vanadium, molybdenum, tungsten, rhenium,ruthenium, and niobium.
 5. The composite material according to claim 1,further including a second metal oxide.
 6. The composite materialaccording to claim 1, further including silicon oxide.
 7. Alight-emitting element comprising a light-emitting layer including aluminescent material and a layer including the composite materialaccording to claim 1 between a pair of electrodes.
 8. The light-emittingelement according to claim 7, wherein the layer including the compositematerial is provided in contact with any one or both of the pair ofelectrodes.
 9. A light-emitting device comprising the light-emittingelement according to claim
 7. 10. A composite material comprising: ametal oxide skeleton comprising a metal atom; and an organic compoundthat is bound to the metal atom by forming a chelate, wherein the metaloxide exhibits an electron donating property to the organic compound.11. The composite material according to claim 10, wherein the organiccompound is an organic compound having any one or more of a pyridineskeleton, a pyrazine skeleton, a triazine skeleton, an imidazoleskeleton, a triazole skeleton, an oxadiazole skeleton, a thiadiazoleskeleton, an oxazole skeleton, and a thiazole skeleton.
 12. Thecomposite material according to claim 10, wherein the metal atom is oneof an alkali metal and an alkali earth metal.
 13. The composite materialaccording to claim 10, wherein the metal atom is one or more of lithium,calcium, and barium.
 14. The composite material according to claim 10,further including a second metal oxide.
 15. The composite materialaccording to claim 10, further including aluminum oxide.
 16. Thecomposite material according to claim 10, further including a thirdmetal oxide.
 17. The composite material according to claim 10, furtherincluding silicon oxide.
 18. A light-emitting element comprising alight-emitting layer including a luminescent material and a layerincluding the composite material according to claim 10 between a pair ofelectrodes.
 19. The light-emitting element according to claim 18,wherein the layer including the composite material is provided incontact with any one or both of the pair of electrodes.
 20. Alight-emitting device comprising the light-emitting element according toclaim
 18. 21. A composite material comprising: a first metal oxideskeleton comprising a first metal atom; an organic compound that isbound to the first metal atom by forming a chelate; and a second metaloxide comprising a second metal atom wherein the second metal oxideexhibits an electron accepting property to the organic compound.
 22. Thecomposite material according to claim 21, wherein a valence of the firstmetal atom is trivalent or more and hexavalent or less.
 23. Thecomposite material according to claim 21, wherein the first metal atomis a metal atom belonging to Group 13 or
 14. 24. The composite materialaccording to claim 21, wherein the first metal atom is any one ofaluminum, gallium, and indium.
 25. The composite material according toclaim 21, wherein the organic compound is an organic compound having anarylamine skeleton.
 26. The composite material according to claim 21,wherein the second metal atom is a transition metal.
 27. The compositematerial according to claim 21, wherein the second metal atom is one ormore of titanium, vanadium, molybdenum, tungsten, rhenium, ruthenium,and niobium.
 28. The composite material according to claim 21, furtherincluding a third metal oxide.
 29. The composite material according toclaim 21, further including silicon oxide.
 30. A light-emitting elementcomprising a light-emitting layer including a luminescent material and alayer including the composite material according to claim 21 between apair of electrodes.
 31. The light-emitting element according to claim30, wherein the layer including the composite material is provided incontact with any one or both of the pair of electrodes.
 32. Alight-emitting device comprising the light-emitting element according toclaim
 30. 33. A composite material comprising: a first metal oxideskeleton comprising a first metal atom; an organic compound that isbound to the first metal atom by forming a chelate; and a second metaloxide comprising a second metal atom wherein the second metal oxideexhibits an electron donating property to the organic compound.
 34. Thecomposite material according to claim 33, wherein a valence of the firstmetal atom is trivalent or more and hexavalent or less.
 35. Thecomposite material according to claim 33, wherein the first metal atomis a metal atom belonging to Group 13 or
 14. 36. The composite materialaccording to claim 33, wherein the first metal atom is any one or moreof aluminum, gallium, and indium.
 37. The composite material accordingto claim 33, wherein the organic compound is an organic compound havingany one or more of a pyridine skeleton, a pyrazine skeleton, a triazineskeleton, an imidazole skeleton, a triazole skeleton, an oxadiazoleskeleton, a thiadiazole skeleton, an oxazole skeleton, and a thiazoleskeleton.
 38. The composite material according to claim 33, wherein thesecond metal atom is one of an alkali metal and an alkali earth metal.39. The composite material according to claim 33, wherein the secondmetal atom is one or more of lithium, calcium, and barium.
 40. Thecomposite material according to claim 33, further including a thirdmetal oxide.
 41. The composite material according to claim 33, furtherincluding silicon oxide.
 42. A light-emitting element comprising alight-emitting layer including a luminescent material and a layerincluding the composite material according to claim 33 between a pair ofelectrodes.
 43. The light-emitting element according to claim 42,wherein the layer including the composite material is provided incontact with any one or both of the pair of electrodes.
 44. Alight-emitting device comprising the light-emitting element according toclaim
 42. 45. A composite material comprising: a metal oxide skeletoncomprising a metal atom; and an organic compound that is bound to themetal atom by forming a chelate, wherein the metal oxide functions as anelectron acceptor.
 46. The composite material according to claim 45,wherein the organic compound is an organic compound having an arylamineskeleton.
 47. The composite material according to claim 45, wherein themetal atom is a transition metal.
 48. The composite material accordingto claim 45, wherein the metal atom is one or more of titanium,vanadium, molybdenum, tungsten, rhenium, ruthenium, and niobium.
 49. Thecomposite material according to claim 45, further including a secondmetal belonging to Group 13 or
 14. 50. A light-emitting elementcomprising a light-emitting layer including a luminescent material and alayer including the composite material according to claim 45 between apair of electrodes.
 51. The light-emitting element according to claim50, wherein the layer including the composite material is provided incontact with any one or both of the pair of electrodes.
 52. Alight-emitting device comprising the light-emitting element according toclaim
 50. 53. A composite material comprising: a metal oxide skeletoncomprising a metal atom; and an organic compound that is bound to themetal atom by forming a chelate, wherein the metal oxide functions as anelectron donor.
 54. The composite material according to claim 53,wherein the organic compound is an organic compound having any one ormore of a pyridine skeleton, a pyrazine skeleton, a triazine skeleton,an imidazole skeleton, a triazole skeleton, an oxadiazole skeleton, athiadiazole skeleton, an oxazole skeleton, and a thiazole skeleton. 55.The composite material according to claim 53, wherein the metal atom isone of an alkali metal and an alkali earth metal.
 56. The compositematerial according to claim 53, wherein the metal atom is one or more oflithium, calcium, and barium.
 57. The composite material according toclaim 53, further including a second metal oxide.
 58. A light-emittingelement comprising a light-emitting layer including a luminescentmaterial and a layer including the composite material according to claim53 between a pair of electrodes.
 59. The light-emitting elementaccording to claim 58, wherein the layer including the compositematerial is provided in contact with any one or both of the pair ofelectrodes.
 60. A light-emitting device comprising the light-emittingelement according to claim 58.